Here is the full list of all 16 Primal Carnage: Onslaught achievements.
Put the hardhat on your own head
Let the carnage begin!
Survive 5 waves in one session
Survive 10 waves in one session
Survive 15 waves in one session
Survive 20 waves in one session
Survive 25 waves in one session
Survive 30 waves in one session
Eliminate each type of dinosaur in one session
Purchase every weapon in one session
Shoot 5 flying venom globs in one session
Get 10 kills with Dual-Wielded Weapons in one session
Kill 3 dinosaurs with a single grenade
Kill the first Raptor using only your knife
Send 10000 dinosaurs back to the Cretaceous
Grab hold of a Compsognathus