whenever I try to test my games, it won't let me input a command. It will let me type it out but not enter it. Help

The website sometimes glitches like this. Don't ask me why.

This could be either the webserver being overloaded (which happens sometimes if you use the web player), or some script getting stuck in an infinite loop.

Could be worth trying again on a different day. And if that doesn't help, try sharing the game and see if it works for other people.