The ending has a somewhat disappointing last level, and then you decide from one of three buttons that makes a different cinematic. That's about it.

And apparently, the sequel they've just announced makes up a different ending for the game entirely instead, which I'm kind of mixed about. On the one hand, those three endings were all just to try and set up the original game anyway, and they were all kinda bad, a requirement to set up Deus Ex's original crapsack world. On the other, I'd still at least want to play it.

Matrix Dragon, J. Random Nutter