Nice and challenging game, would say there should just have a door open that leads you to the next area, rather then having to wait for a hole to appear, have it grow big enough to fall in, and wait for your character to land in the next room. It takes way to long and breaks the flow of this fast pace game. Also the bullet hurts enemies when the bullet just sits there, should be only when the bullet is fired that hurts the enemy.
Thanks for the review! I can see how the hole breaks the flow a little bit, the thing is i want the player to waste time so that the timer will get closer to 0: making the game harder. What i could do if i make the transition faster is make more rooms per stage.