Here is the full list of all 16 Tetradecagon achievements.
Beat your highscore 10 times.
Die 5 times on one level without progression
Beat your highscore.
Perform a 360 while bouncing the ball.
Lose control of the ball seconds immedietely after bouncing it.
Die for the first time.
Die immediately after the grace period on the first level.
Use the Konami Code.
Die 100 times.
Perform a 540 while bouncing the ball.
Beat the highest level, Icosagon.
Beat your highscore 50 times.
The illusion of allusion.
Suck 500 times.
Glitch the ball out of the polygon.
Enable epileptic friendly mode.