Here is the full list of all 30 The Final Specimen: Arrival achievements.
Kill all enemies in Level 2.
Defeat a boss without taking damage.
Bomb all autos in Level 3.
Blow up all soda and pizza in Level 4.
Max out lives (hard mode only).
Watch every cutscene in full.
Beat the entire game without taking a hit.
Collect all helper tokens in Level 7.
Stay underwater long enough to start the countdown timer.
Die in every way possible.
Find the secret room in Level 5.
Get nailed by the moving spike wall in Level 1.
Finish the game with the maximum number of lives.
Get crushed by a building in Level 8.
Beat the entire game without dying once.
Bomb 50 enemies.
Kill 50 enemies by punching.
Complete Level 7 without being spotted by a cop.
Fall into a pit in every level with pits.
Outrun the homicidal cop living beneath the streets of Doofusville.
Kill 50 enemies with the Golden Horseshoe.
Destroy all the red cars in Level 3 using the Golden Horseshoe.
Defeat all Rooster sub-bosses in a single game.
Attempt to kill a Level 5 Ghost using the Golden Horseshoe.
Kill The Legendary Lost Officer with the Golden Horseshoe.
Beat The Final Horse on Easy Mode using no cheats.
Beat The Final Horse on Hard Mode using no cheats.
Collect all Golden Horseshoes on Easy Mode.
Collect all Golden Horseshoes on Hard Mode.
Beat The Final Horse on Hard Mode with the Infinite Continues cheat.