Glad you figured out SOME way of opening it at last, at least... in the worst case, it's always possible to manually copy code from the GM Beta and recreate objects in the main project (should be a lot easier with two instances of GM so you can actually compare stuff properly, vs doing it by hand from the .gml / .yy files)
(The one thing that's not super obvious is that I use the GUI "Variables" interface for all the enemy stats, they're not set up by code in the Create event)