Here is the full list of all 20 Tentacles: Enter the Mind achievements worth 200 gamerscore.
You equipped the rainbow trail and the pink eye.
You completed the Libido Layer!
You picked up 3 tombstones without dying.
You reached a multiplier of 8!
You went from one pitstop to the next without killing any enemies!
You selectively killed Kamikazes without killing any other creatures!
You found the loophole in the knife
You cracked your first egg!
You just bought yourself some more time!
You held three rubber duckies at once!
Have a Kamikaze orbit Lemmy
Get 5 snipers to aim at you simultaneously.
Attach all three tentacles to the oscillator screen on the science box
Use all 3 powers.
Kill 5 enemies with 1 bomb.
Crack a purple egg.
Crack a black egg.
Kill a Rammstein without using any powers.
Complete the entire Regret Layer.
Reach a multiplier of 10.