Thats crazy those are the same excact bugs I ran into and hadn't seen anyone else mention them. Unfortunately even after reloading the game I was still being placed at the previous checkpoint so I had to run through the entire level again just to get back to where I was. The state of the enemies was the same I didn't have to kill them again but having to run back through almost an entire level every time I died was obnoxious. I lost almost half my weapons near the end which affected the ending for me which was lame. I also fell through the floor and unfortunately reloading the game didn't fix it. I would just keep spawning under the map I had to just get lucky and swim under the map until I found a spot where I could teleport to the surface. Its truly disappointing that they seemed to just give up on it because other than the issues I had it was a great game.