Thank you a lot ! Yeah, I know some people got stuck because I did not specify you can click the empty slots in the bar to retrieve the controls. From now on I’ll try telling people to read the “Controls” section in the description to avoid such problem :)
If you're looking for ideas, perhaps you could make it so you're able to break keys which aren't made out of just one block (such as the space key) into smaller parts which you can then use in the world, then stick back together using a pickup like glue or something to recollect or use as a full piece again.