Deus Ex is the type of game that wants you to feel involved in the world it has created. In this world you have a verity of ways to approach many situations, stealthfully sneaking, hackerly hacking, or psychotically killing. Even at the time the gameplay took a bit of getting use to but once you got passed the playability you found a believable cyberpunk world that you could get into.
One of the aspects i always liked about the game was the cool augmentations you could do to upgrade yourself. Sometimes useful, sometimes not, it was a drastic enough change that you generally felt a difference after augmentation.
If you enjoy the made up gamer word "immersiveness" then you will enjoy Deus Ex.
