2027 is a modification and a prequel to Deus Ex 1.
Excellent mod, with a quite good storyline, pleasant maps and a sufficient duration. But the best point is the new stuff: the new weapons (including the spiders, drones and new grenades), the new enemies, the new skills and the new augs bring many new fighting/playing possibilities. I actually fighted much differently than in DX.
But there are some bad points. The difficulty goes from very hard in the first half to very easy in the second half of the game. Several times, especially in the first half, infiltration is made impossible for no justifiable reason (enemies who know where you are without seeing you, alarms that sound while being bypassed...), turning from time to time this true DX mod to a basic FPS. Also, I didn't get the same feeling as in DX or in its better mods about the different "factions" of the game: I didn't care that much about the choices I made. And it didn't felt like a DX prequel to me at all.
Still, this mod deserves a 9/10, with a 10 on creativity.