Deactivate all 3 scorpion spawners in the canyon

Kill at least 50 enemies with flames

Kill the spider queen

Kill 3 enemies with a single buzzsaw 2 times in a row

Finish a level with accuracy >= 85%

Escape the prison

Finish a level without losing any lives (hearts)

Finish a level with 0 lives left and health left < 25%

Finish a level without taking any damage at all

Kill 300 enemies with barrels, crates or rocks

Don't let core protector boss hit you with his melee attacks even once

Kill the bugs without using the flamethrower in the subway level

Don't let acid worms hit you while you're riding a boat

Find dopefish in the subway level

Get into dangerous places in the subway level

Kill the skull helicopter boss

Don't breath gas in the gas chamber trap

Don't let creatures in the jars get destroyed in the laboratory level

Destroy all the creatures in the jars in the laboratory level

Defeat the buddy boss

Kill professor Nathan and escape the facility

Beat the game on hard difficulty

Beat the game on easy difficulty before beating it on normal or hard

Find the secret level