From left to right:
Mechanoid. He's wondering if you saw his CNNPU (Central Neural Network Processing Unit).
Solnettian (aka "Werewolf") greets you in a neutral manner.
Viltzian looks kinda interested in dissecting you for studies and then assembling you back together.
Human (aka Earthling, aka Federate-fag) is detested by all that alien scum.
Terran is having some good time with big bottle of rum and rather thick cigar. And huge rifle.

In the background, Precursori and Infernal Projection (complete with two Pawn Drones) watching you as if you're nothing.

This list misses few races, like Imperials, Enclavers, Hurricaners, Cavers, Oskolians, and various Viltzians hosts.