Great game but a few caveat:
the button has different gameplay in the first levels and the rest of the game (at first it is permanent but then it requires a rock to be active)
it s not clear at first glance that the yellow thing cannot be collected unless you have a key (but the first level let you figure that out so it's not a big deal)
most importantly the physics do not work properly and can easily lead to soft lock, the game need a restart button !!!
That said Enjoyment is still a 5/5, I really liked it