“Z-Type was specifically created for Mozilla’s Game On. I immediately wanted to participate in the competition when I first heard of it, but the deadline seemed so far away that I didn’t bother to begin working on a game back then. Fast forward to this tweet announcing that the deadline was only one week away – it took me by surprise. I still hadn’t even began working on anything. The thought of just submitting my earlier game Biolab Disaster crossed my mind but was immediately dismissed again.”
Great sound, great graphics and in the higher levels quite difficult.
Source 1: http://www.phoboslab.org/ztype/