How to make my projects run faster?

Whenever I'm nearing the end of a project, the performance always starts slowing down. This makes it harder to tell how fast something is actually moving and it ruins the experience of the player as well. How can I prevent this?

Btw, here's the link

Just a guess, but maybe your clones are making clones, so the total number of clones grows exponentially? That is, you have a MAKE A CLONE block in a script that you think only the original sprite is running, but actually all the clones run it also.

You keep making posts like this, but never show us the project(s) you're talking about.

Good point ty, I added it

I think they should so that people can figure out what's wrong.