what an awesome demake, i loved how you balanced the different weapons to make them stand apart from how you use them in the original doom, with the shotgun you really have to get in their face, and the chaingun slowing you down is a nice idea to make the plasma gun feel like a great upgrade. i was underwhelmed by the rocket launcher though, i think sometimes it wouldn't take an imp down in one rocket, and i would make it have a larger blast radius.
Love the maps and the sprites too, you made everything work great with the limited palette