TurboWarp is recommended, https://turbowarp.org/1378162653 to make sure the map is big as possible, I made it the size of the current FPS multiplied by 90 on turbowarp. don't think scratch could handle that, also the counter up there is your current FPS.
credits to GarboMuffin, who created TurboWarp so we can stop suffering with lag on scratch. link to TurboWarp on it's own. turbowarp.org: https://turbowarp.org/ inspired by this project: https://scratch.mit.edu/projects/169477788/ which is a map of scratch users who have more then 1200 followers, (including deleted or banned accounts)