Make sure to run in turbo mode. (Shift+Green Flag) Move around with the arrow keys. Try to beat the lowscore. Since some mazes are harder than others, each has it's own lowscore. Once you have finished a maze, press space to get a new one. Press L to see all of the Lowscores on each maze. Admittedly, this doesn't randomly generate mazes right there, but they were randomly generated and tested to make sure they work. (The solver has been known to make mistakes before though.)
@squig3 for some custom scripts Inspired by @CrafterMaster360 (for making a project I remixed) and @ottodue (for complaining about my remix). So then i made this one. I'm currently having some issues with updating this, scratch won't let me save it, so i won't be able to implement any changes any time soon (i've been trying a few)