Making a FPS like Doom or Duke3d

I am new to unity and scripting. How hard would it be to make a game that has similar gameplay to Doom or Duke3d with sprites for weapons and enemies and all the powerups? I want to have keycards to open doors and moving platforms too. Im gonna make all the levels in Blender.

Btw im using the free version of Unity.

No offense but that’s a pretty dumb question.

But if you want to make a game with hmm

player abilities - moving, shooting, jumping, collecting basic items
AI - shooting back, moving (few enemy types)
game - opening doors, moving platforms

if you want to have only that things in game it can take one day if you’re really good at scripting. depends on your skill. I would say 1week for myself.
but I’m not rly advanced. It will take you few years to learn all the stuff that Unity is giving you.

The tricky part will be the AI and GUIs(if you want them complex) but the rest, a piece of cake!