Cook a Grenade for too long.
Unified Coupling Theorum
Help the Barnacle and Headcrab find true love.
Kill a Marine with their own grenade.
Kill 10 enemies with Snarks.
Conduct all of the questionable research experiments.
Hyper Saturation Conundrum
Drown in Lambda Core's coolant.
Kill an Icthyosaur with either the Tau or Gluon.
Kill 10 enemies with a reprogrammed Sentry.
Kill a Barnacle with a Satchel.
Refuse to insert the specimen into the Anti-Mass Spectrometer.
Get killed by your own Snarks.
Kill 10 Airborne Headcrabs using the Shotgun.