A demo for some code that creates a scrolling level that can be expanded as large as you want. Use the left, right, and up arrow keys to move the black square around a scrolling world, and use r to reset the level. On the top right, there is a ring that brings you to the next level.
Click see inside and read the comments to learn how this works. If you'd like to copy this code into your own project, I'd appreciate it if you linked to this project in your notes and credits. Credit to Abitofeverything's project bypass scratch size limit (https://scratch.mit.edu/projects/308218638/), which taught me the technique that allows sprites to be moved to any location.