Kingdom Hearts 1.
The combat feels really, really good. The game will require you to utilize guarding, counterattacking, and dodgerolling to their maximum potential, and to really take positioning into account. It's super satisfying to guard an enemy combo, push it back, dodge roll forwards to close the gap distance, and then whale on it with your Keyblade.
It's also pretty fucking tough. It doesn't feel like a game intended for its younger audience, but hey, there it is.
The level design is amazing. Hollow Bastion in particular. I love how massive everything is, and how many paths there are through the level. The sense of scale, and the verticality make it one of my favorite levels of all time. Destiny Islands and Traverse Town are really great as well, with Traverse Town having a TON of secrets that you can find as you return to it after obtaining new abilities, and with Destiny Islands having some really catchy music. http://www.youtube.com/watch?v=EQdwwW0FMGshttp://www.youtube.com/watch?v=4nlCNVewMjAhttp://www.youtube.com/watch?v=g25QXnhVijQ
^a couple of good pieces from the game
My gripes with the game are:
-camera often gets stuck behind objects. the sequels fix this, though
-the gummi ship minigame is too easy. you can literally hold X and make it through everything alive.
-special attack abilities (sonic blade, ars arcanum, etc.) should have been mapped to the Triangle button. It's a hassle to have to move my fingers from the thumbstick to the dpad, then to press it a few times to get to the proper menu selection. By the time you do that, you've taken a ton of enemy damage.
-offensive spells are too weak by the midgame. as soon as you get the cure spell, it's hard to justify wasting mana on some damage over a spell that can heal you back to (almost) max health.
-goofy is worthless.
-summons (with the exception of tinkerbell) are worthless.
Funnily enough, I actually like the story of the first Kingdom Hearts. It's not nearly as convoluted or insipid as the sequels. Sure, it's weird, but weird in a good way.
Overall, a fantastic game. Holds up well today. Shame the sequels lose all sense of difficulty.