My favorite vide game trailers and why:

Dishonored (2012) Trailer:
https://www.youtube.com/watch?v=zcSc4uBc3nQ

Reasoning:
I love this trailer, it really sets the mood for the game with a lot of information given to you without text or words. The artstyle, feel, and gameplay of the game is shown with a wonderful accompanying song that gives you chills on it's creepiness factor.


BioShock PS3 trailer:
https://www.youtube.com/watch?v=wEgSmmlv5Ok

Reasoning: Another beautiful mood setting trailer that really pulls you into what you are looking at with a just wonderful background song, and a great choice of visuals, and a good mix of gameplay without spoiling too much about the game itself.


Resistance: Fall of Man UK Launch trailer:
https://www.youtube.com/watch?v=1azn7bMKdvg

Reasoning: Great voiceover to get across the feeling that they wanted for the game.  For what they had, they did a great job of editing it together. The whole thing has this subtly creepy feeling to it, which is what the game felt like in general. I remember watching this over and over again.


Metal Gear Solid Portable Ops TGS 2005 trailer:
https://www.youtube.com/watch?v=NxblLyuWxaM

Reasons: Metal Gear Solid games almost always tend to have great trailers, while the dialog on this one boarders on cheesy at times, the powerful score, and and solid writing carry it. Gameplay shown covers the depth this game had, as well as it's humor.


Halo 3 Announcement Trailer e3 2006:
https://www.youtube.com/watch?v=o5EroNgD54k

Reasons: While I didn't really like the end product as much, I thought this trailer was breathtaking, and I really like the wonderful mix of art, music, dialog and direction. It's a shame they didn't show any gameplay. Still well directed, and got everyone in the mood to 'finish the fight'.

Halo 2 e3 2003 Trailer:
https://www.youtube.com/watch?v=9i-4foLur0g

Reasoning: The first gameplay shown of Halo 2. This is possibly the best gameplay trailer I'd ever seen. Again it's a shame the game didn't live up to this. I still hold out hope to find some way to play that E3 Demo level in my lifetime. The trailer mixes a dose of hype, with awe and wonderment, by showing the continuation of Halo 1, and showing earth for the first time in the series, as well as a truly massive levelscape, and an insane amount of atmosphere for what it was. Great music, crazy visuals, and just an insane scope.


Kingdom Hearts II Teaser, Deep Dive:
https://www.youtube.com/watch?v=Kh_3PVnI7no

Reasoning: While it's only a teaser, and is all pre-rendered, this trailer is very well directed and opens more questions than it gives answers. This showed us the new face of Kingdom Hearts which looked darker and more insane. The real game didn't live up to the trailer, but to this day, I think this trailer is fantastic.


Tearaway Gamescom 2012 announce trailer:
https://www.youtube.com/watch?v=NK6_QvdxyXQ

Reasoning: This trailer is just fabulous, showing us not only the world this new IP lived in, but all the cool mechanics, the silliness, and overall awesomeness that is Tearaway. This is coupled with media molecule's amazing taste in music.


No Man's Sky VGX 2013 Trailer:
https://www.youtube.com/watch?v=RRpDn5qPp3s

Reasoning: This trailer showed us, why yes, you and me, we care about this new game. It's just amazing, and this trailer shows us just why it is, with colorful visuals a nice tune and all ingame gameplay, it's just spot on.


No Man's Sky e3 2014 Trailer:
https://www.youtube.com/watch?v=nLtmEjqzg7M

Reasoning: Just like it's initial trailer, this just inspires awe and wonderment. It told me, I need this game. I can't really put more into words other than yet again a great trailer consisting of all in game gameplay, no voiceovers, and a grand scale.


Ni No Kuni: Wrath of the White Witch e3 2012 trailer:
https://www.youtube.com/watch?v=4MznAY8Es5c

Reasoning: While it has some sorta cheesy dialog, this trailer shows just how cutesy and wonderful this game is, showing some of the story, as well as the phenomenal music, art design and the heart this game had. Bravo


The Last of Us e3 2012 Gameplay Demo:
https://www.youtube.com/watch?v=8ZYkj0glnqs

Reasoning: Only second behind Halo 2 in possibly the best gameplay demo I've ever seen. Tense, brutal, colorful, dark, thought provoking, and overall just fantastic. I was sweating at the edge of my seat watching this.


Alice: Madness Returns Launch trailer:
https://www.youtube.com/watch?v=cFrs5UGB-ns

Reasoning: Showing us the twisted bizarre world we are going to experience as well as showing us just who creeped out we are going to be. Showing lots of gameplay through the entire game giving you a good idea of what you are in for.


Journey Debut trailer:
https://www.youtube.com/watch?v=2BEComrj0A4

Reasoning: Just watch it. The art, the music, the concept. Just everything about this trailer shows why the game was so damned good.


Michael ad:
https://www.youtube.com/watch?v=fj96XYhwTFI

Reasoning: While not directly an ad for a game, this ad was dedicated to all the gamers who had supported the PlayStation 3. It showcases a lot of fanservice in terms of characters, and overall was a blast to watch.


Child of Eden announcement trailer:
https://www.youtube.com/watch?v=xuYWLYjOa_0

Reasoning: Funky visuals and a great soundtrack get through the idea of the game. Sadly the game didn't live up this trailer, but the trailer is still nothing short of beautiful. The colors, a artistically style. Very nice.


Beatles Rock Band Intro Trailer:
https://www.youtube.com/watch?v=76lTJL7kQYo

Reasoning: This was all they needed to sell most buyers on this game, a completely fantastic trailer which was just the intro to the game. No gameplay, but at this point, people already knew what to expect with the Rock Band series of games. All around, still fun to watch as many times as the game gets started up.


Mercenaries 2 "Oh No You Didn't" trailer:
https://www.youtube.com/watch?v=NcJyCdbC08c

Reasoning: While this trailer doesn't really show much of the game, it's in it of itself a great ad. Silly, catchy and memorable. Totally unlike the final game.


Driver: Parallel Lines "Trailer 5":
https://www.youtube.com/watch?v=BlbtfmXyDlM

Reasoning: A great trailer for a decent game. It shows all the solid direction, and great chase scenes the game has to offer. Solid music and totally full of gameplay and drama.


Battlefield Bad Company teaser:
https://www.youtube.com/watch?v=Ex12fxhtumk

Reasoning: A great teaser for a game no one expected. A single player Battlefield game, which is…. comedic? Fourth wall breaking and silliness abound. It also shows off environmental destruction and some of the characters.


Assassin's Creed Ubidays 2007 trailer:
https://www.youtube.com/watch?v=92PAh0ad5F0

Reasoning: A new IP that looks insanely awesome and original about assassins in the crusade era. Lots of gameplay with a wonderfully synced song to go along. Yet another game that didn't live up to it's amazing trailers. Still, a treat to watch to this day.


Assassin's Creed Launch trailer:
https://www.youtube.com/watch?v=nJXal99JfRw

Reasoning: Yet another great trailer synced up to this time, an original song. Again,  it shows a lot of the game, and really gives you something you just want to get your hands on.


Gears of War "MAd World Cinimatic Trailer":
https://www.youtube.com/watch?v=SquC26-vdtU

Reasoning: While I didn't like Gears of War, this is one of those trailers that stays with you. It doesn't say much, but it makes you remember it. Great camera movements and direction.


The Saboteur teaser:
https://www.youtube.com/watch?v=DbrLgQqbO34

Reasoning: Another one that gives little information but sports an interesting concept and some pretty art, enough to get you wanting for more. Pretty much what a teaser is designed for.


Coded Arms Assault TGS 2006 trailer:
https://www.youtube.com/watch?v=KoIFrQbkhD4

Reasoning: Sadly this is a trailer for a game that was canceled in development. It doesn't stop it bring being interesting, visually attractive in it's art style and it also sports a solid background song. It always makes me sad we'll never see the final product.


Strong Bad's Cool Game for Attractive People Debut trailer:
https://www.youtube.com/watch?v=qqxS7-0GKyo

Reasoning: Basically the prefect way to make a trailer for this game. I can't even imagine how to do it better.


Metal Gear Solid 3: Subsistence GC 2005 trailer:
https://www.youtube.com/watch?v=pmTcEIF51ys

Reasoning: A michinima of the new Metal Gear Online for PS2. It showed off some of what to expect in all of Kojima's humorful online mode for Metal Gear Solid 3. While it's not true to what you'd actually experience, the combination of music and silliness makes for a fun to watch trailer that really got me pumped to play Subsistence.


Mirror's Edge Trailer 1:
https://www.youtube.com/watch?v=2N1TJP1cxmo

Reasoning: A trailer for one of the most original first person games of it's time shown in all real time gameplay. It's art style, style of play and overall feeling were shown here, and it was fantastic, and still is. Though the trailer ends on a cliffhanger: See part 2.


Mirror's Edge Trailer 2:
https://www.youtube.com/watch?v=KLwKMjUxvQQ

Reasoning: Just as fun to watch as the first one, this shows us even more of the game world, and just makes to want to play it even more. Beautiful music and visuals and nothing but gameplay. Fantastic.


LittleBigPlanet 2 trailerS:
https://www.youtube.com/watch?v=Oy_a3oCDzRA

https://www.youtube.com/watch?v=Ky-JUL0SDDs

https://www.youtube.com/watch?v=xVIVvaP1On8

Reasoning: These trailers are just magical and make me want to grab a few friends and coop the game all over again. So darn good. LittleBigPlanet is just like happiness incarnate.


Resistance 3 GC2011 trailer:
https://www.youtube.com/watch?v=sp3F4MKv5Jg

Reasoning: Iconic and atmospheric, it doesn't show any gameplay, but really gets the damn point across. A fantastic game, and a fantastic trailer. It utilizes solid colors, and a small pallet and a lot of artistic shadowing which makes it almost look like a graphic novel.


Metal Gear Solid 4 e3 2007 trailer:
https://www.youtube.com/watch?v=L33CLNWXTdg

Reasoning: Showing a lot of story, and ending with an insane fight scene, this trailer is probably burned into my retinas for how many times I watched it. Good stuff!

Metal Gear Solid 4 e3 2006 trailer:
https://www.youtube.com/watch?v=6cyTiS1wSZc

Reasoning: One of the most epic trailers ever made in my opinion. Slow paced, a little brooding, slowly making it's way through the setup, style of the game, and the themes it covers. Characters you've not seen in a while, and a lead up to a tragic ending, followed by a crazy fight scene.


Deus Ex: Human Revolution "Cinematic Director's Cut Trailer":
https://www.youtube.com/watch?v=roK7Wc6thzM

Reasoning: Just watch the trailer. It shows the concepts for the gameplay, the feeling of the world, and the style the game goes with. The atmosphere, voiceovers, and music are all just perfect. Props to whoever directed the trailer.


Metal Gear Solid V: The Phantom Pain trailers (Reveal, e3 2013, e3 2014):
https://www.youtube.com/watch?v=03nUMw7japI

https://www.youtube.com/watch?v=UMyoCr2MnpM

https://www.youtube.com/watch?v=yfoPfF2u1to

Reasoning: I can't even explain how much I love these trailers. So well directed, great scene chooses, great music, great graphics, great themes, dark, interesting, and overall.. I need the game.