Commandos

Are the Commandos demons or zombies or a little of both? They seem like the zombies of a former human, but then again they have a demon-like voice and they're the only zombies who really say anything.

Zombie, or Demon, or Half-Demon/Half-Zombie?

Well since they burn up when they die I assumed that they were humans turned into demons (Not zombies) by some satanic process that you see in one cut scene (Betruger pushing a marine down and the pentagram appearing on the floor). It explains why they all look the same and have the same headgear and clothes even though they're all supposed to be former humans at some point.

they have to be part demon anyways, zombies dont have new bodyparts and such (i.e the tentacle) they may miss some (i.e head, arms)

They're a little of both. Normal zombification won't produce anything as impressive as the commandos.

Even though the commandos are dumber than the Z-Sec guards. The melee ones, you can just duck under the tentacle and blast them in the pants.

They die like demons so I would guess a demon.

Maybe they took the soul of a human and encased it in demonic form?

Though I must admit the commandos were basicly retarded.

the zombie squads were much more difficult.

I could never tell if they were demons that were shaped like humans or if they were simply posessed humans.