| icon | info |
|---|---|
 | Brownian Motion Pass the toilet paper to the Scientist in need. |
 | Caffeine Extraction Perform surgical caffeine extraction from 20 vending machines. |
 | Calculated Trajectory Kill 10 airborne Headcrabs using the Shotgun. |
 | Centripetal Attraction Kill 20 Enemies with the Hivehand. |
 | Convection Refinement Ruin the microwave casserole. |
 | Dead Reckoning Kill an Assassin with the .357 Magnum. |
 | Digital Wizardry Kill 10 enemies with a reprogrammed Sentry. |
 | Ethically Questionable Conduct all of the questionable research experiments. |
 | Futile Resistance Kill 10 Enemies with Snarks. |
 | Gray Matter Propulsion Headshot 20 Enemies with the .357 Magnum. |
 | Hyper Saturation Conundrum Drown in Lambda Core's coolant. |
 | Inflammatory Actions Kill a Headcrab using fire. |
 | Kinetic Repulsion Kill a Marine with their own Grenade. |
 | Mega Hertz Kill 5 Enemies with one Grenade. |
 | Nuclear Fishin' Kill an Ichthyosaur with either the Tau or Gluon. |
 | Permeable Infrastructure Use the alternate path in Office Complex. |
 | Premature Expulsion Use an entire clip of Gluon ammo in one continuous shot. |
 | Prophylactic Suggested Get overtaken by a Headcrab's ample anterior. |
 | Proverbial Tinkerer Interfere with the alarm and laptop in Anomalous Materials. |
 | Quantum Capacitance Overcharge it anyway. |
 | Rare Specimen Send the Hidden Hat to Xen. |
 | Remote Detonation Kill a Barnacle with a Satchel. |
 | Resonance Procrastinator Refuse to insert the specimen into the Anti-Mass Spectrometer. |
 | Unified Coupling Theorum Help the Barnacle and Headcrab find true love. |
 | Universal Gravitation Get killed by your own Snarks. |
 | Prolific Popper Kill all Protozoans in the Borderworld. |
 | PhD in Pacifism Don't kill any Vortigaunts in the Borderworld. |
 | The Rarest Specimen |
 | One Step Ahead Kill 10 Enemies with Tripmines. |
 | Stealth Technology Escape the Hangar in Surface Tension without alerting the Soldiers. |
 | xen when |
 | Our Brains And Your Brawn Assemble all the possible Scientists and Guards at the end of Office Complex. |
 | Less Than Desirable Consequences Die in the AMS Beam before starting the experiment. |
 | Orbital Trajectory Skip the opening Xen island with a secret jump. |
 | Following the Rules |
 | Doctor’s Signature Deliver the finishing blow to Gonarch with your Crowbar. |
 | Gonad Glider Get whacked into oblivion in the ledge fight. |
 | Post-Mortem Interval Find each member of the missing research teams. |
 | The Plan |
 | Unquestionably Ethical |
 | Contest Propellant |
 | Laser Immunization Complete Interloper without taking any laser damage. |
 | Black Mesa Decathlon Winner Escape the Gargantua’s Lair without taking any damage from Gargantuas. |
 | Anti-Matter Over Mind Kill a Controller without killing any of its mind-controlled Vortigaunt slaves. |
 | Specimen GG Take out all three Healing Crystals in Nihilanth’s Chamber at the same time. |
 | Late for Work Defeat Nihilanth in under 4 minutes. |
 | Limitless Potential Accept G-Man’s offer of employment. |
 | Rather an Anticlimax Decline G-Man’s offer of employment. |
 | Pepperoni Precipitation |
 | Well-Done Cook a Grenade for too long. |
