Really cool game, fellow tetris-dev! :D
It took me a while to realise you don't actually get points, and you only go to the next level by "losing" tetris and winning the "secret" afterwards.
Really cool and well made, but it's a bit of a shame that there aren't any scores. I realised that there's no reason to even go to the regular doom-mode, just collect ammo, and once you've got enough, the most efficient thing is to just lose tetris quickly and jump straight to the bossfight.
Nonetheless, superb game!