Awesome puzzle mechanic butI would say a couple tweaks are needed on the difficulty curve (might just be me tho :P). I love how the cube gets back in place when you die, really cool!
But please, please I beg you, when you export GameMaker games DO NOT export the NSIS installer, you can export a .zip or an .exe but please NOT the NSIS intsaller :c (no hard feeling tho :P)