Here is the full list of all 16 Phantom Trigger achievements.
Did you read the text at the very end of the game?
Smash all crystals
The tree falls!
Take a trip with Pam
Solve all puzzles
Unlock all combos
Kill 50 frozen enemies
Congratulations, you skipped the story
Do you know what insanity is?
Turn off the last TV set
Kill everyone
Kill 20 enemies in co-op mode
Die in co-op mode
Beat all bosses in co-op mode
Chop down the tree
Arena completed.