Random 2D/3D level generator

Created over a weekend using GameMaker: Studio, this was me learning how to create random levels using HeartBeast's YouTube tutorial, then the GM:S documentation to figure out the Direct 3D functions.

The level generation code is modified from HeartBeast's own method - to accommodate the 3D functions each block of the wall is a separate object, whereas HB uses just one object to draw anything - but then he is only doing it from a top-down perspective!

I've uploaded the source code. Feel free to take it apart, use it and abuse it for any of your own games. No credit necessary. It's not exactly well commented, but have at it! All I ask is you show me what you've made.

But man oh man... GameMaker: Studio sucks for creating 3D games, no wonder people say don't do it!

In the 2D world, you'll notice a flag to represent a goal. This does nothing other than play a sound currently. There is no point to this "game".

The movement is meant to be reminiscent of old dungeon crawling games like Hired Guns, Captive, Bard's Tale or Whales Voyage. So you only move in "steps" and rotate 90 degrees at a time.

The controls are:

Left arrow - rotate anti-clockwise
Right arrow - rotate clockwise
Up arrow - move forward
Down arrow - move back

O - go back to main menu
P - generate a new maze
Esc - exit game