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