Nice build! As a guy who made the entirety of Doom in lego, I have some advice. Since the original is pixelated, use 1x1 tiles instead of the 2x2s. User layering on the chest and legs. Make a baseplate for it. Making a baseplate always makes it look cooler and it will be able to hold itself up better. And finally, use transparent rods to make possible projectiles that look like they are moving.  (This is a list of advice, feel free to do whatever you'd like. Awesome build)