The underwater theme really fits with the creative use of the oxygen tanks for the 10 seconds theme. That mechanic made me really hurry along which I appreciate in a platformer lol. I liked that you decided to mix platforming and bullet hell which I haven't seen as often. It would be nice if I had checkpoints in order to not have to restart every time. I was not sure what the timer was for in the room with the red bullets? The HTML5 worked for me! Nice job