Hi, Thanks you very much for playing the demo! I'm really sorry you had to experience such a heavy glitches. It looks like the forest was very poorly optimizated, so the game crash there if the computer is not powerfull enough. I just uploaded a new version with several optimizations.
Oh, if you want to try the game again, you can swap between characters with right click (this advice didn't show well due to the glitch) but it's still really recommended to play with a controller, if you had one.
Thanks again for your impressions!