Here is the full list of all 22 UltraGoodness achievements.
Defeat the Office Guy
Defeat the Machines of Terror
500 enemies killed by flames
250 enemies killed by flames
250 bombs thrown by the player
Defeat the Tree of Evil
Kill 5 000 enemies
100 enemies killed by flames
100 bombs thrown by the player
10 000 bullets fired by the player
50 enemies killed by flames
Kill 2 500 enemies
5 000 bullets fired by the player
50 bombs thrown by the player
2 500 bullets fired by the player
Kill 1 000 enemies
Unlock all companions
Kill 500 enemies
1 000 bullets fired by the player
Be friends with Satan
Kill 100 enemies
Catch bunnies having fun