Good game so far, but twice I've fought the Sigma Boss 1 and fallen through the floor both times. fall through the floor that is 6 segments bouncing up and down and it's the third segment (if 1-2-3-4-5-6 starting on the left) I fall through. Kind of annoying. I can't die and have to exit stage. Would be nice if there was a "die" option instead of only leave stage option. Otherwise good so far. Also, while fighting the burrowing boss as the second boss on that stage I ended up becoming invincible somehow, fulll health and nothing could damage me.