Syphon Filter Theory TAS notes

Theory TAS: https://www.youtube.com/watch?v=tAryjNFaqK8

==General Notes==
1. Bizhawk simulates PS1 load times (or something close to them). Someone playing on ePSXe or PS2 with fast disc speed will probably save 5-10 seconds per stage.
2. The PAL version of Syphon Filter runs faster than NTSC by somewhere in the 10-20% range (more testing needs to be done on this).
3. It's occasionally possible to skip intro cutscenes for levels. I've seen it happen on stage 1 and 6. I'm not sure what triggers it.


==CBDC Cover Sections==
1. Guards spawn in fixed locations based on a) how many guards currently exist, and b) where Gabe is looking. There may be other factors as well.
2. The bomb is disarmed at a fixed interval after a certain number of guards have spawned. There's sometimes a bit longer delay if an agent is being shot.
3. There's a fixed distance Gabe can be away from the agent without failing the objective. Ideally, you want to be right at the border when the objective completes, but sometimes there's a tradeoff between how quickly you can kill the guards you need and how far you can be from the agent.
4. It doesn't matter if the agent dies after the objective completes.


==Quick Targeting==
You can use the Target Lock (R1 by default) to swivel Gabe and align him for a Manual Aim (L1 by default) headshot or limb shot on enemies. This is useful for enemies you're forced to quickly snipe, like Kravitch, Mara, Benton, etc. There are some important tricks to it:

1. Gabe must raise his weapon before you try to lock on. If you press while his weapon is relaxed, the cursor will appear, but he won't swivel the camera to pinpoint the enemy and the manual aim will be off-center.
2. You have to hold target lock while standing still for long enough to complete the camera swivel to center the enemy.
3. In rooms with multiple enemies close to each other (like Mara and the nearby guard), you'll want to position the camera so that the target you want is already closest to your line of sight, or you'll target lock the wrong one.
4. Gabe won't swivel to face enemies that are moving or crouching (not 100% sure about this).


== 1. Georgia Street ==

-The opening roll saves a couple frames.
-The 1st guard in the CBDC section always spawns in the corner. Sometimes only 1 guard spawns toward the back, but as long as you kill 3 before heading back to to the front of the building you should complete the objective.
-Getting the extra M16 ammo isn't required, but it only loses about a quarter of a second and makes a lot of animation skips much easier.
-You can use the auto-aim to line up your shot on Kravitch's head. Hold R1 just long enough to secure Gabe's lock on him before switching to L1 and firing. Then sweep left to get the array.
-Ignoring Lian's call in the subway security room saves about a second, but Gabe lowers his weapon just before the prompt for the power box comes up, so it's difficult to time this animation skip. You have to practice it to know when to fire.

== 2. Destroyed Subway ==

- I like to strafe right as I'm approaching the climbing section to let the guard on the first catwalk appear on my radar, then target and kill him before climbing. Then you can strafe left, double-tap down to quickly turn around, and do the climb.
- There are two ways to do the fast final grab of the climb.
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- (Buffer method) Tap forward while Gabe is still holding his weapon out. Gabe should move so his shadow is in the exact center of the whie column he's standing on. Note that if you tap forward after Gabe has lowered his weapon, you won't be able to get into this position, as he'll move too far forward. Once he's positioned (and has stopped moving), press and hold L2 and Left on the d-pad simultaneously.
- (Fast method) Hold left strafe, and then hold Left+up on the d-pad shortly after (while still holding left strafe). There's a precise timing to this input of about 5-6 frames Left Strafe, then you have another 4-5 frames to press & hold Left+Up. With practice, you could memorize this rhythm and get consistent at it, but it's riskier. You can do this with the analog stick as well, but a pure 45 degree angle might be easier to get with the d-pad.
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- Just as the CBDC agent says "cover me", you can safely fast turn and have a guaranteed guard spawn behind you. Kill him and move to the boundary, wait briefly, then move forward. This guard won't spawn if you're facing the exit.

== 3. Main Subway Line ==

- Make sure Gabe is looking to the right of Mara before doing the quick target technique for an easy headshot, or he'll pinpoint the guard instead.

== 4. Washington Park ==

- CBDC Cover 1: Like with Stage 2, face away from the next destination and do a quick turn just as the agent says "cover me" to ensure the guard spawns behind you, then kill him and run on ahead. This should always work.
- CBDC Cover 2: This is the hardest cover section in the game. It needs the most guards killed and seems to have the longest timer to defuse the bomb after the threshold is met. To be safe, I kill 5-6 guards and make sure there are none near the agent when I leave. You can usually take out guards with 2 Colt-45 shots while crouching if they're quick targeted.
- CBDC Cover 3: Still sorting out the best position this one, but sometimes I can get away with 3 guards. The boundary is pretty far into the next area.
- CBDC Cover 4: The position I use is to try and force the 4th spawn to appear on the way to the tennis courts. It doesn't always work, but I had decent luck with it.
-Hostages: I ignore the first guard and tap target lock twice to quick swivel to the hostage guard and then get an instant headshot. It's not bad to make sure, though.

== 5. Freedom Memorial ==

- I'm trying a left-right strafe to keep Girdeaux from returning to his walk animation, but reset (or pause) the delay on his flamethrower long enough to get extra shots. I don't know how much faster this is yet, or if it's worth the trouble.

== 6. Expo Center Reception ==

- First room: This position behind the middle column allows you to kill both guards and have a free Stonehenge room without Phagan ever seeing you. Make sure to kill the far guard first or you'll auto-fail the mission. Fire 3 shots as quickly as you can.
- Egypt guards: The first one won't fire back right away if you shoot him from far enough away, and it forces him to run forward and puts him in a good position to pick up his HK-5. It's only worth the risk if you're confident. The method I use for the last 2 is scary, but pretty consistent with practice.
- Benton: Quick-Targeting Benton for leg shots is very finnicky for some reason. If Gabe is already aiming toward him when you press R1, sometimes he won't swivel. I'm not sure how to account for this except to try and do it exactly the same way every time. I do a crouch when I reach him to buffer my movement for ignoring Lian's call.
- Locked door 1: Crouch and swivel while shooting to take out this lock without manual aim. It takes some practice to understand the right angle.
- Locked door 2: A 45 degree angle to the lock is pretty good for shooting it out.
- Staircase room: Leaving the balcony guard alive can force one of the other guards in this room not to spawn, so with quick-climbing, it's possible to survive being shot climbing back up. Still a bit risky.
-Elevator room: Hitting the switch without manual aim is very difficult, even when you have the right angle. You can hit it much earlier than it seems. Probably best to do a manual aim strat though.
- Moon room: Swap to the K3G4 just before falling into the exhibit to skip the stumble animation. Sometimes 3 catwalk guards spawn, and they can push you off, so it might be best to kill them all rather than try to climb up with any still alive.

== 7 . Expo Center Dinorama ==

- Ignore Lian's call to save a second.
- This path through the fish room makes the guard in here difficult to kill. Experiment to find the best place to start shooting him, but make sure he dies or his shots will aggro Mara.

== 8. Rhoemer's Base ==

- Manual Aim + Left Strafe right as the stage starts lines you up for a head shot on this enemy. Quickly move around the truck and copy the path I take to avoid his angry buddy from seeing you and causing a stage alert. Alert should happen around when you're killing your 4th guard to get some extra PK-102 ammo.
- My path through this stage tries to plan for where big groups of guards like to spawn, and gets pretty good luck. The speed at which I move may prove to be good at manipulating no major spawns until Gabrek.
- If Gabrek gets spooked early, killing him and opening the gate becomes more laborious and loses probably 5-10 seconds to stay safe. It's not the worst idea to kill him before planting charges on the fuel tank.
- No manual aim on the motion sensor power is probably not gonna be consistent RTA but it's worth trying.
- Shoot the guards on the path back from the motion sensors as soon as they spawn. Gabe will automatically find them. This works for all far-away guards from here on.
- In the last room, steer clear of the barrels as you go up the ramp. Hug the left wall as soon as you can to break the enemies' line of sight.

== 9. Base Bunker ==

- No-aim switches is probably not realistic RTA.
- Ignore Lian's call again.
- Try to save a bit of PK-102 ammo for the start of Base Tower.

== 10. Base Tower ==

- Shooting the dish controls right at the start and starting the fight immediately is a risk, but can potentially save around 8 seconds.
- If possible, grab the flak jacket during an unhittable phase of the fight so you don't have to grab one at the start of the next stage.

== 11. Base Escape ==

- Truck Skip: After climbing up into position, and with a one-handed weapon equipped, target lock the guard above you until Gabe stops turning, then press Circle (combat roll) and hold Right-Strafe shortly after (before the animation starts, but not at the same time). With practice, you should be able to use this setup to always land on the truck.

== 12. Rhoemer's Stronghold ==

- Markinson's first call is the only one I found that didn't save time to ignore, as long as you answer and skip it right away.
- Using the beaker to kill the scientist is cute but might not be the fastest strat (which is good, because hitting the beaker is actually really hard). Faster is probably to kill both the scientist and the guard with head shots to get the guard's PK-102, which you can use to quick open the Gas Grenade and PK-102 boxes.
- Ensuring you target the right scientist in the trio keep the gas cloud away from the key card and lets you take a straight line to the PK-102 box.
- Using a gas grenade to kill the scientist might not be consistent if he's aggro'd early. This could take more research. That said, Gabe knows where he is and will throw the grenade his direction even if the window isn't broken.
- Last Test Subject: This is dangerous, if the extra guard spawns he's likely to hit the beaker and kill you. The first one might be able to as well. This strat has potential but a lot can go wrong.
- Ramp Gas Grenade: Use the texture of the floor as a visual cue for when to throw this. It'd be prudent to stop moving very briefly to let the gas cloud shrink and grab the keycard at the outer edges of its hitbox.
- Rooftops: Avoiding a stumble animation when exiting the window is very tough and the smart thing might be to just drop down then do a moving roll.

== 13. Stronghold Lower Level ==

- Right-to-Left: There's a lot of little ways to adapt this to keep it safe. Falling into the second room has produced some really stupid deaths (including by falling through the floor and into oblivion).
- Killing the scientist in the 3rd room of this chain with a gas grenade is tempting if the guard doesn't spawn, but lethal if he does. You also can't quick climb with grenades equipped.
- Manipulated Scientist: The scientist you lure by shooting at the top of the ramp can be in a lot of different locations based on how long it took to do the 3 rooms, so this isn't always a clean kill with a gas grenade. If you want to save one for the catacombs, this is a good one.
- Ignore Markinson's call again and position yourself behind the test subject while waiting for the prompt to fade
- Labratory: Unarmed scientists will kneel and stay put if you touch them. I use that to gas the one at the start of this room as I'm leaving and avoid manually headshotting him. Keep the target on him and you can throw it as you circle the corridor.
- Ignore Markinson's call again.

== 14. Stronghold Catacombs ==

- Right now nothing speeds the first section up. I just goof around during it.
- Phagan and Lian both have scripted paths through the stage and will stop if a guard is blocking them, you bump into them, or you crouch.
- Phagan walks slowly if he's near a guard (possibly an aggro'd guard), but sometimes keeps running (possibly if he's already past them?)
- There are too many spawn locations for guards in this stage for all of them to appear, so sometimes it's possible to force advantageous ones to spawn behind you so that certain ones won't appear ahead.
- Using the G-18 to headshot guards as they appear can save time vs. letting Phagan get to them and having to clear them out while he waits. It could take a lot of work to consistently keep him moving by knowing which guards to force not to spawn, which ones to kill and when, and which ones to ignore.
- This is known by most active runners already, but shooting Lian twice makes her run continuously through the stage, not stopping when guards are in her path.
- I get ahead of Lian in her section, but this is difficult to manage. At one point she runs down a dead end and turns around, it may be better to do the section behind her until then and get ahead of her for the finale.
- You can leave Lian behind after the final staircase and run for the exit.

== 15. Pharcom Warehouses ==

- Warehouse 36 Door: lining up this grenade shot is somewhat tight. You have to be far enough past the guard so Gabe doesn't throw the grenade at his feet. If you can do this trick, it saves a little over 2 seconds.
- Warehouse 69 Door: This is where grenades save a lot of time. Use this video as a guide for when to throw them. It's not always possible to get a no-stop entry into the warehouse without blowing yourself up, so hesitate if you're not sure.
- Fence Gate: Sometimes the guard buildup here makes it dangerous to get through here and you'll be forced to throw a grenade to scare them away. I've also had good results from sticking to the right side to break up the blue guard's line of sight as I approach.
- You can get the K3G4 during either visit to the tunnels.

== 16. Pharcom Elite Guards ==

- Taking the path I take heading up to Warehouse 85 keeps any guards from seeing me and the guard inside won't be aggro'd until I move past him.
- My K3G4 management in this stage is not ideal given the strats I eventually used for the endgame. You can kill the guard that shoots me as I run past the flaming barrel with 4 shots.
- Warehouse 74: In runs, I take the left path on the way here and the same one on the way back. It's a slower route but it aggros fewer guards.
- Grenades: I ended up using fewer than I thought I would, so this box could be skipped with tighter routing. It probably costs about 2-3 seconds to get.
- The roll down to the final Viral Carrier is the best strat I could figure out: It lets you kill the grenade thrower before he can get one off, it doesn't aggro the 2 tunnel guards to ambush you during the forced Lian call, and you can crouch walk backwards while mashing Triangle to tag the carrier.
- Tunnel: After killing the first two guards with the K3G4, I purposely ignore the barrel guard to skip a spawn later. Notice after I turn the corner there's only 2 guards there instead of 3 -- I can just run past them and not use any ammo, taking minimal damage.
- The last sets of 2 guards in this level I head-shot to make sure they're cleared out smoothly and can't damage me as I run past them, to save Flak Jacket ammo for the next stage.

== 17. Warehouse 76 ==

- 1st Fire Roll: There's a setup here that saves even more armor that's worth looking into. If you save enough, you can do an extra fire skip just before the elevator later.
- 2nd Fire Roll: This won't kill you if you have around half armor and full health, as long as you do it right. After climbing the boses, hold forward and press roll immediately afterward, to ensure you're doing a moving roll with a 2-handed weapon from as far back as you can. This is risky and only saves about 4 seconds, but it's definitely an option.
- 3rd Fire Roll: This can be done with a 2-handed moving roll, but I have better results from a 1-handed standing one.

== 18. Silo Access Tunnels ==

- If you're confident in your laggy elevator room, you can skip the flak jacket box and get what you need from the first guard.
- The 2 guards before the laser grid is a good place to use a grenade and avoid stopping to aim or burning a lot of K3G4.
- Lag Room: Hold forward and right-strafe when doing the combat roll off the high ledge to land in the alcove. The timing for killing the 2 guards is pretty tight if you don't want the 2nd one to kill you. If you don't get the animation skip on the console, the 3rd guard becomes a bit more dangerous to deal with.

== 19. Tunnel Blackout ==

- Girders: Hang from as far left on this girder as you can, then drop. Despite the length of the fall, I haven't died doing this yet.
- Final Push: Leave the high-up guard alive as you enter the last section to force one of the final trio not to spawn. You need to collect the last catwalk guard's flak jacket after being shot to survive this push, and you'll likely need a full K3G4 clip to take out the last two in front of the door. The guard in the alcove may hit you during the fade out, if you want to try to target and kill him.

== 20. Missile Silo ==

- Getting killed on the lower level is always a possibility, so this late in the run, it doesn't hurt to have a setup for killing one or even both of the guards down there.
- Radar Room: I press Square to throw the grenade, then start using manual aim to arc it up shortly afterward so Gabe stands still for longer. If the room doesn't load correctly, it's possible the grenade could go out of bounds and not kill the scientist. K3G4 is always an option instead, cause sometimes the scientist does unpredictable things.
- Last 2 Guards: The no-stop grenade strat I'm doing involves pressing square as I clear the corner, then targeting the guard I'm facing before Gabe throws it. Then swap to either the Biz-2 or K3G4 before climbing to be able to do a fast climb.
- Rhoemer: Select gas grenades while falling from the missile control console and get into position to throw it where Rhoemer will spawn. Again, you can press Square to throw the grenade before you've aligned Gabe to the spot you want it to land.