Thanks for your constructive feedback. I initially planned to add more stuff to the gameplay, like traps and triggers that would make it not so easy to reach the end of the level (the coin)
They are even in the codebase, if you look at the sourcecode on github. But i did not manage to add them in a (for me) satisfying way in the two weeks.
And maybe that would have exceeded my (self-imposed) challenge of "max 13 kB" :-)