Haha, fun game ! (and not laggy for me, it seems important to tell xD)
I found an OOB glitch though : everytime (kinda) you destroy a blue block at the surface by smashing it, you can go at the left edge of the screen (where there is no transition) and fall infinitly out of bounds. To reproduce simply : at the very first screen, smash a bluc block and hold left =). You can trigger the boss fight by going right, and escaping it locks the game. Fun glitch !
~MetalFox Dioxymore