A very fun SNES game, which is the sequel to Mega Man X (also for SNES). It is extremely similar to Mega Man X, in that it uses the same engine, and you go through 8 levels, fighting a boss at the end of each one. The bosses are generally very hard, but can usually be beaten easily by using a weapon obtained by beating another boss (every boss has a weakness, so there isn't one easy boss to beat first). In a few places throughout the game (including the final boss), there are 3D wire-frame enemies to fight, which is the only significant difference from the Mega Man X engine.

While trying to beat the 8 levels to get to the final level, you can also attempt to get Zero's 3 parts by beating the 3 special bosses, who are much harder than the other bosses because no weapon is super-effective against them. Zero's parts don't appear to do anything, and it's possible to beat the game with or without them and think that they don't make a difference. However, you must fight Zero on the last level (right before the final boss, which makes the level so much harder) if you do not have all of his parts. If you do have his parts, it plays the (IMHO) coolest cutscene in the game, where Zero destroys Sigma's fake Zero-like robot, then chases Sigma away by shooting his super-powerful weapons at him very quickly, while the best MegaMan-like music in the game plays.

Whether you fight him or not, Zero, with his amazingly powerful weapons, goes off to destroy some computer, leaving you to fight the final boss by yourself. When you beat the game, it says some stuff which seems sort of deep and philisophical, and probably has something to do with Mega Man X3 (which I haven't yet played).