For a quick game, I'm happy with the results, it could be much better in a number of ways but in such a short time frame it's OK.

I would love to implement smoother scrolling, more monsters, more wall variety, more levels.  

Overall I didn't have many problems, it was pretty straight forward.  Having the limitations I put in place helped me to finish the game in time.  I didn't really have any bugs or issues which caused a lot of time to fix, which is what I was worried about.  The main bug I found was that I could see the skulls through walls. No problem, it was just the draw order which was incorrect.

Any questions, let me know below!  Thanks!