use arrows and wasd. LOAD ALTERNATE MAP USING L To show/hide editor lists, press space. You can load a map using L. The compiled map file to be loaded is stored in the savemap list, which you can right click, then click import(see inside). Use my map editor to make maps for this (if you care) NOTE: Unclosed vertices freeze the program. make sure that the final value in vertices is "\".
More testing. Works much better when viewing geometry from outside, as walls behave oddly when you walk past them because I can't do calculus. Vertex Cross Product fries my puny brain.