You'll be happy to know that the accuracy of the move counter has been one of our highest priorities for the final game. We have sped up the self-destruct sequence dramatically too (although there's a shortcut in the jam version-getting out of the mech before self destructing) The fact that you don't have to finish a level with a gem was a bug we have fixed for the final version of the game too.
For the undo move it would be really cool but I am afraid that the complexity of the game combined w the fact that it is on gameboy/gb studio make it practically impossible to implement.