Really interesting controls. Sadly I got stuck on the first trampoline level, it was quite confusing, because everything killed except the flag, but the flag didn't do anything, I just bounced off the top of the flag.
I did some testing and I suspect it is your level loading logic that is buggy.
I tried hitting the spike over and over again and there is a low chance that it actually drops to the next level (the level with coins). When the spike didn't work sometimes an image popped in for 1 frame which looked like coins (perhaps the coin level). Also when I completely reload the page and the game sometimes the 2nd level is this trampoline level.
I suspect, that the spike works but the game loads the wrong level.
PS: this is the "buggy" trampoline level by the way
