Small visual update

I've added outlines to the walls, button and doors, as you can see in the attached images. It's a small change, but it's already far better than how it looked before.

Due to the way I had done the walls previously and how gamemaker worked, I ended up drawing the outlines of the walls manually on each level. The doors and buttons were easy though, as I just needed to change the sprite once.

I'm thinking of making the background more interesting too, probably a simple moving checkerboard pattern, but I want to add audio before that.