Check out my super mario bros 3 engine https://scratch.mit.edu/projects/203689206/ The hitboxes suck on this, I know.
NOTE: This is an old buggy project. Thanks to brad games and griffpatch.. 200th love by Brad-Games! What the community is loving!- 9/18/17 What the community is remixing- 9/21/17 _______________________________________________________ updates Sep.26 2017- Koopas added and bug fixes. Thanks to @badquality for helping on somethings. This is not complete. This a work in progress Oct 19 2017- Pipe changed to Super Mario world pipe, Bug fixes. Nov 11 2017- Improved sensors, you should no longer get killed when you jump on a koopa. If you do just tell me. Nov 14 2017- Yeah, sensors are still bad I'm trying to find a way to fix it. Made a few changes but not much. To prevent a glitch that happens sometimes, you may want to press green flag when you die. I will try to fix the glitch. BTW thanks SO much for 40k views!