Pretty impressive and fun! I have to admit, part of me isn't sure if I should rate this high because, as much as I like it, it is just Doom and that already exists and was made by someone else, so I'm not sure where the credit is due, if that makes any sense. Haha, I'm definitely overthinking it, but yes, it was very impressive to see this in Pico-8 and I had a lot of fun blasting my way through the all-new custom levels. I did have some frustrating aspects with it: the shotgun felt very weak and inaccurate compared to the original, a lot of my shots would just disappear for no reason, and it felt like the hitscan zombies would open fire too fast occassionally. Also, felt like the levels were a bit too corridor-y and maze-like at times: would love to see more variation quicker if it's possible! Still, very nice work!