I need help! I don't know what is making my project lag, and if you have any suggestions for me, please let me know!

The project file is here: Project

Please do not remix, steal, or in any way use my project other than to test to see what is wrong with it.

In the “Achievments” sprite, you have a custom block called “Check Advancement #3” that runs without screen refresh.

Turn off “run without screen refresh” and it should fix this problem.

If you have a custom block running without screen refresh every frame or in a forever loop without a wait then it will lag the project due to the script being ran multiple times every frame, 30 times a second. I'm sure the reason is self explanatory. Hope this helps.

It did, thank you very much! I will be sure to leave an homage to you in the credits!

This is the problem when you post the same question multiple times. This answer was given earlier here in response to your other post. Please only post your problems once.