Creating an "Impossible" Paper Mario Cartridge Explained

Text-based explanations for the "Impossible" Cartridge video:

File 1: Castle Basement Softlock
Developed by: r0bd0g, Stryder7x, & Bonecrusher1022

After Mario falls into the Bowser's Castle jail, there is a lengthy sequence involving many partner uses to escape the prison and its outskirts, which we refer to as "the basement." Because of many gaps requiring Parakarry, lava pits requiring Lakilester, and the cracked jail wall requiring Bombette, this region is a bottleneck for glitches and skips. It's very limiting; saving in the basement without the partner Lakilester results in a softlock.

Lakilester cannot be skipped if we wish to complete the game. Luckily, we desire the opposite here! We can get to the basement without him by using Peach Warp to skip Chapters 6 and 7. Traditionally, Lakilester is used to perform the Peach Warp glitch, but we can do it with Sushie instead. One method involves Save Block Storage, which can be manipulated into a form of partner ability storage. We trick the game into thinking we're using Sushie's out of battle ability, which in Sushie's case, means swimming. But we aren't on water, so as you could imagine, things get weird. Diving allows us to get out of bounds virtually anywhere, which is an asset since sloped collision does not know how to properly handle swimming. In the English release of the game, a frame-perfect dive must be executed in the spiky ball passage to avoid an unwanted softlock since the cutscene locks our movement. Eventually, we can retrigger the eruption when Chapter 5 is in a completed state. The next Princess Peach intermission plays, and the current chapter is skipped. This "Peach Warp" can be repeated until story progress is set to Chapter 8, where we can invade Bowser's Castle, end up in jail, and save the game without Lakilester. Reloading the file will allow you to still play, but good luck finding a way out.

File 2: Flood Room Softlock
Developed by: Rainchus & Malleo

Within Bowser's Castle is a water puzzle to reach a key needed to unlock the nearby door. Mounting Lakilester's cloud is useful for clipping into corners and walking on water here. In one particular instance, we can fall through a panel in the background thanks to Lakilester's y-coordinate being offset by the water level. This allows us to go underwater, so we can return to where we came from and save. The water level is saved to the file, and with it comes an invisible wall blocking access to the second room - which is essential to resetting the water level. No matter how hard the player may try, there is no known method of reaching the loading zone behind that invisible wall under these conditions.

File 3: Swallowing the Castle Key
Developed by: r0bd0g & Stryder7x

A lot of doors are locked, so in typical video game fashion, we must find conveniently located keys for them. What if the key wasn't accessible? Would the player give up and go home? The answer is yes, because we've done just that. By swallowing the key.

Items have different classifications in Paper Mario. The relevant ones for this glitch are "Items" and "Key Items." Unlike the regular Items, which can be consumed, Key Items are unique, often essential for sidequests or completing the game. The maximum number of key items that can be held at a given point is 32. Through natural story progression, this would never become an issue, so the developers didn't bother adjusting the limit. But with glitches that can duplicate Key Items or skip using them, we can end up with the maximum. The limit isn't the issue though. Future Key Items are problematic, though. If obtained through a treasure chest or handed to Mario through a cutscene, the Key Item simply disappears and is never copied into inventory. But if we collect a Key Item on the field, such as the Keys in Bowser's Castle, they start behaving as regular items! Having access to Key Items in the Regular Item inventory means we can toss them, sell them, or... eat them. Because the Castle Key is flagged as "obtained" and is not present in the Key Item inventory, the player will never be able to unlock the door and save Princess Peach.

File 4: Goompa Limitations
Developed by: Exylophone & Stryder7x

One of the most customizable puzzles here involves Goompa, with a goal similar to File 4 in the Evil Cartridge video. Since opening the partner menu with Goompa out crashes the game, and all other partner swap alternatives can be permanently disabled through the controlled use of Super Blocks and deletion of the Mailbag, saving the game before required partner abilities will make the file impossible to complete. For instance, saving at the beginning of Bowser's Castle with the previously mentioned conditions met would prevent the player from progressing beyond the jail, since Bombette cannot be switched out to blow up the cracked wall. The player will witness a rather obvious game crash should they choose to attempt opening the partner menu with Goompa out.