It's either Army of Two, Spec Ops or Infamous.

Hint for #13:

Eating the bodies of four specific characters grants the protagonist something.

Aaaand, I'm behind again. Cue post streak!

#17: Assassin's Creed: Brotherhood (Ubisoft, 2010) - PS3 (also on 360 and PC)

This is where the series was annualized. Many people dismiss Brotherhood as "AC2.5, just an expansion pack". And you know, they're probably right - but I had so much fun with this game, and that's what matters right? In terms of story, I prefer AC2, because there I could see Ezio's full development. Here, he's fully developed, so there's not much to it, but it's still entertaining though. The gameplay adds some things that make the whole game a cakewalk: recruiting assassinis, the crossbow... but personally, I don't play games for a challenge, I play them to have a good time. And a good time I had with this one. I like it as much as AC2, with AC2's plot putting it a liiiiitle higher on the list. However, this game has a GODLY multiplayer. I got to level 50 not because of a trophy, but because I just couldn't stop playing it. It was my favorite competitive multiplayer of the gen BY FAR. Strangely, AC3's multiplayer didn't interest me in the slightest. I couldn't tell you why.

Also, despite all the issues with Unity, I still greatly enjoy this series, despite missing most of them. Here's hoping AC Victory delivers.

#16: Assassin's Creed II (Ubisoft, 2009) - PS3 (also on 360 and PC)

Oh Assassin's Creed 2, what a delightful surprise you were. Back when AC1 was first released, I got hyped. It reminded me of Prince of Persia (which I enjoyed), so I made sure to play it as soon as I had the chance. Had a blast with it... for a few hours. Then I became INCREDIBLY bored by that game, it was sooooo goddamn repetitive, and every city looked the same, which didn't help.

So when the sequel was announced, I couldn't give two shits. "Eh, looks like they're improving some things. Nice". But a friend of mine had this game, and he let me borrow it and HOLY SHIT, what a huge, HUUUUUGE improvement. This game right here is a contender for "best sequel ever". I didn't got bored a single time with this game. The story was more interesting. The characters were FAR more charismatic, Ezio is actually one of my favorite characters of the gen! Minor details like double and air assassinations went a long way in improving the game. I could write a huge post with all the things that impressed me (compared to the first game). In the end, one of my favorite games of the 7th gen.

#13 - Switch between 5 playable characters

#13 hint 2 - Play the original game in this game

Super Metroid? Could it be that easy? Or is this a trick? =P

Hint for #15: God from the machine 3

hint for #14: this a franchise owned by one of the Big 3. Despite just having one game, it has a very passionate fanbase that begs for the return of this IP to this day, nearly 15 years after its release.

#14
Super Mario Bros. 3 (NES, 1990)
guessed by TruckOSaurus

It would be difficult to find a person, young or old, male or female, diehard gamer or novice, who has played Super Mario Bros. 3 and didn’t enjoy it. Among the thousands of video games released over the past thirty years, it might be the single most popular. Although the Super Mario franchise had veered slightly off the road with Super Mario Bros. 2, it returned to form with Super Mario Bros. 3, arguably the best NES game ever made. Designed with the same platform elements typical of its predecessors, Super Mario Bros. 3 introduced several additions, including mini-games, many new power-ups (e.g. Tanooki Suit) and an overland map that allows players to select which levels to play and which to bypass.

Ico?

Conkers Bad Fur Day...?