Here is the full list of all 12 Heckpoint achievements.
Kill every boss
Purchase every gun from the shop
Kill one of each enemy type
Get a 3 kill streak
Purchase every special from the shop
Destroy 100 meteors
Max out all player stats in Gene Works
Purchase every passive from the shop
Get a 6 kill streak
Get a 10 kill streak
Unlock all worlds
Kill 10,000 enemies