I bought this game originally, after playing the demo. The first thing I remember was the first level sucked.. Sorry, the swamp level was terrible. I try not to remember that as much as possible.
What I do remember, however, is the rest of the game. Particularly the fights against large squads of Nazis, which turns into a huge, frenzied slashfest. This game does an incredibly good job of making you feel like an invincible psychotic whirlwind, and finishing off a group of poor witless soldiers is the most entertaining thing ever. There's nothing quite like bouncing from one Nazi to another while they squirm helplessly shouting "get it off me! GET IT OFF ME!" Brings out a certain level of sadism and glee at the same time.
That and thinking it ended all too soon. Oh well, this game is awesome while it lasts. Except the first level, but just cheat through it and forget it exists...