Jak and Daxter is a solid, yet unoriginal platformer that fails to stand out from the pack.
We've already established that the plot is incredibly Zelda in nature, but that Zelda influence carries on to the character design as well. None of the characters in this game would look out of place in Ocarina of Time or Majora's Mask, for example; in fact Jak is essentially a reimagining of Link with exagerated proportions and without a hat. Jak's silence and all around uninteresting personality does little to shake the feeling that he's nothing more than a Link clone.
Thankfully the game is saved by Daxter--a truly hillarious videogame character. Most of the game's personality and comic relief falls on Daxter's shoulders, and for good reason--he's the only truly interesting character in the game. (There are some pretty funny background characters, but none of them really have a big role in the game). He has some really funny dialogue, and his victory dances when you get a Power Cell (Jak and Daxter's equivelant to a Star in Mario or a Jiggy in B-K) are always humorously choreographed.
One of the things that this game does have going for it are the impressive (for their time, anyway) character animations. This is probably the first game to truly feel like a playable cartoon, as all the characters move in a disney-like way. The voice acting is also superb by videogame standards.
But it's the gameplay that really counts in a videogame. While Jak and Daxter doesn't have any glaring gameplay problems, and it's certainly quite a bit of fun, I can't think of anything particularly spectacular about it. It's just not a very original game when it boils down to it. You won't experience anything in Jak and Daxter that you haven't experienced in another platformer. The open world gameplay (a huge metroid-esque world that's not really divided into individual levels) fits the game well, but it's already been done in Banjo-Tooie and Donkey Kong 64--and those games had the benifit of warp-points that made travel easier. Jak and Daxter, however, does not. And traveling the huge overworld can be a drag at times. Also, this game does little to shake the stereotype that platformers are nothing more than collect-a-thons. The tag-team gameplay feels nearly identical to Banjo Kazooie; except without all the cool special moves. I will say that the game has a near perfect camera system though, that puts games like Mario Sunshine to shame (in the camera department, that is)
The presentation is a bit "meh" overall. The PS2 isn't known for it's textures, so it's not surprising that the game looks a bit jagged compared to the better looking Gamecube and XBOX titles of it's time, but the game is quite bright and colorful, and looks very nice despite some blurry textures. The soundtrack, I'm afraid, is pretty pathetic. There isn't a single memorable tune in the whole game.
There aren't any glaring problems with Jak and Daxter. The thing with it is it's just so uninspired and samey. You can find the game for $5 used, and if you're looking for some cheap fun for your PS2, this would be an adequate place to spend it. But you could probably buy Mario 64 or Banjo-Kazooie for the same price, and both of those are much better games.