I am new to this, and this is my first game that I have coded! I had my start button coded so it worked. Now, it isn't working for some reason! Will anyone be able to help me code it better and/or give me suggestions on how to improve it?

Here's the link to the game:
https://scratch.mit.edu/projects/410179282/

Your first green flag script for the chicken is doing nothing unless you're pressing space key at the same time as clicking the green flag - you don't have a loop so it only checks the key at that time. No need for the stop this script blocks either. You have a lot of different scripts there, some of which can be combined to make your code easier to debug.

You're trying to set a cloud variable in a forever loop which is too quick - you need 0.,1 seconds between cloud writes.

If you watch the stop sign above the project you'll see it stops immediately so you probably have a stop all block somewhere. Looks like taxi4.