Is there a way to redo levels? I beat level 4 without collecting the new command, since I was curious what would happen and figured it wouldn't softlock me. I think it softlocked me.
Hm, yes, that would be a bug! We should have made the level impossible to solve without collecting it. Sorry about that!
Never rely on something being impossible. You should make sure you get the upgrades automatically at the end of the level just in case.