I thought this was a great idea and really impressive to get the mechanics working in such a short period of time! Everything worked well together and I felt like I could quite easily understand what was going on and how things worked.
The effects at the edge of the arena and when you got shot were a nice touch and the themeing was really coherent and polished!
I did find it quite tricky. I really wanted to be able to collect loads of code blocks to experiment but i was struggling to find many (I guess that's a testament to how fun the idea is!).
Nice work, great job!