Any good sci-fi games I could get on Steam?

Just wondering, as I can't really seem to find any with the search.

Already have:

• Mass Effect 1&2
• DOW 1&2
• Half life 1&2 + Episodes
• KOTOR 1&2
• All the Fallouts, save Tactics and POS

How about these:

- Deus Ex

- Dead Space

- S.T.A.L.K.E.R.

- Bioshock

- Metro 2033

- Shattered Horizon

- Alien Swarm

- The Dig

- moonbase alpha

- chrome (not for everyone)

- the ball

- portal

- crysis

- stalker

- singularity

etc.

bigger question TC what sci-fi games ARENT on steam?

How about these:

- Deus Ex

- Dead Space

- S.T.A.L.K.E.R.

- Bioshock

- Metro 2033

- Shattered Horizon

- Alien Swarm

- The Dig

JN_Fenrir

Alien Breed

Bioshock 1 + 2

Dead Space

How about these:

- Deus Ex

- Dead Space

- S.T.A.L.K.E.R.

- Bioshock

- Metro 2033

- Shattered Horizon

- Alien Swarm

- The Dig

JN_Fenrir

^ What the people above me said + Chronicles of Riddick