Just to be clear, we're talking about games in which your player characters actually travel through time, not games in which you use time manipulation (so no Braid). We haven't yet seen all of the new Back to the Future games from Telltale, so they could very much belong on this list eventually. Until we get to judge those games yet to come (which is certainly one of the first things I plan to do with my time machine) these examples will have to stand for now as the most creative uses of the time travel concept in gaming.
10) Crash Bandicoot 3: Warped
Nobody really has nice things to say about the 'coot anymore, and while his franchise has made a few missteps, that doesn't mean we should overlook how tremendously fun the classics were. Though Warped might be a typical run-away-from/toward-the-camera-and-grab-stuff platformer, there is enough variety in most of the stages to keep it much more interesting than the average level-hopper. You get to use a bunch of different vehicles, play as Crash's sister and fight Tiny in a Roman Coliseum. Plus, it is kind of one of the top selling PlayStation games of all time, so it's worth some recognition. There's also a secret world, if I recall correctly, in which you get to race men in black near Area 51, and that kind of level design merits some sort of respect.
9) Teenage Mutant Ninja Turtles IV: Turtles in Time
An arcade and SNES classic: colorful, fast-paced, insanely fun and full of great opportunities to chuck a foot soldier OUT OF THE SCREEN! So what if it follows the typical level parade of most time-travel platformers (dinosaur age, pirate age, train age, etc.)? The game is so well-loved that there is, of course, that 3-D version, Reshelled available on Xbox Live but as cool that is, there's no topping the feel and vibrancy of the original (seriously, playing this game is like drinking a mai tai with your eyes). As a side note, I'd forgotten the hilarious Huey Lewis-ian theme song. I wonder if they kept that in the remake...
8) The Lost Vikings 2
Speaking of classic SNES games that have been remade in 3-D, by no means should you bother with Norse by Norsewest, the weird-looking PC version of this classic: seek out the original at all cost. Like the original game, this is an excellent action/puzzle platformer that requires you to use the specific skills of three different characters (one who can run and jump, one who can attack, and one who can defend himself and... other things) to collect objects and make it through your typical assortment of "time" levels. What makes this game so much better than its predecessor is the addition of two badass extra characters to the mix, a werewolf and a dragon, both capable of attacking. Timing is everything here,
7) Timesplitters 2
I'm frankly a little surprised that there haven't been more first-person time-travel games, although the lack of rapid firepower in most of history might have something to do with that. The first one is a little too simple and the third is too goofy, but this is the perfect distillation of the series. The Quantum Leap approach, casting you as a different character in each mission, was an excellent way to tie disparate storylines together while still involving characters like Captain Ash and Harry Tipper, and though the cartoony spoofiness is there, we also get more sober chapters like the Neo-Tokyo and Siberia segments. And yes, the multiplayer is better in 3 but 2 is the most balanced overall and a general alien-blasting good time, Goldeneye ripoff or not.
6) Live a Live
Whispered on the winds of nerddom, this Famicom game was never released in the US but it's been unofficially translated and is something of an emulator legend. You play as several characters in different stories throughout time, unrelated at first, from prehistory to the far future. Eventually, you discover that each character has faced an incarnation of the same immortal demon king, and in a unique twist, you get the option to either finish the game using a combination of the heroes, or play as the villain and destroy them all, one by one. I can kinda understand how distributors might have thought the subject matter a little too...uh..."culturally specific" to appeal to a wider audience (the "near-future" section is about a telepathic mech pilot and shares many similarities with anime, even including its own theme song.). But come on! You get to be a cowboy, a ninja, a kung-fu master and a robot in the same game! It's a genuine crime that more people haven't played this one, and to top it all off, the boss music is quite calypso-funky in a way more RPG fight songs should be.