Just click the “Off” button to slow down time. Apply this to any scratch program by backpacking the “SlowMotion” sprite while it is off and adding it to any program. The button is also draggable in case it covers an important button, therefore it can be moved. You can also toggle the effect by broadcasting the “ToggleSlowMotion” command. While it is on it will also slow down the editor, so be careful! You can also make the game run at a higher or lower rate by changing the value in the wait block (it has a comment with additional instruction).
This project works but running a wait block inside of a “run without screen refresh” custom block. This causes the game to prioritize the wait instruction before running any other code until the wait timer is over. This causes the game to hang for a short time. This is why it can easily be run in any project.