Hello! I'm working on a platformer game. Right now, I want to get my character to change costumes when I press Space. However, when I do that and the costume changes, the character freezes, unable to move left or right until it switches back to the normal costume. Could you take a look at it and let me know what the problem is?

scratch.mit.edu/projects/170554708

That is the way you have coded it.
Moving left or right and changing costumes are in the same loop. When you wait 0.2 seconds while changing costumes, the whole loop waits and doesn't get back to check arrow keys.

There are a few ways to solve this. Here are some:

1) Use a broadcast if the space key has been pressed. Then the changing costumes and wait 0.2s is in a separate script which will not hold up your loop. (Do not use “broadcast and wait” or nothing will change).

2) Put the code testing for space in a separate loop.

3) Use a “When space key pressed” block.

Thank you very much, I used the “broadcast” method, and now it works perfectly!

Also, to simplify your costume changes. You don't need left and right facing costumes. You are already pointing in direction in your scripts. So you only need a costume that faces right and a costume that faces right punching. Let the point in direction handle pointing left and right. Then you can simplify the punch script to, if key space pressed, broadcast punch.

Wanted to throw this out there in case you started creating leg movement with the animation, didn't want you to create all the sprites costumes for facing left and right. Just note that using this method, when you draw your sprite they have to face the right.

https://scratch.mit.edu/projects/170611368/

Ah, I didn't think about that, thank you again, @mstone326! Looks like I'll have to add you to the credits again XD
And, as a note, I was actually planning in making leg movement, thank you for telling me before I went on with that!

P.S - Do you have any idea how I could make a combo of punches, when space is pressed repeatedly? Right now I have two punches in a row, but they are triggered by a single space.