hey there! Glad you're enjoying the game so far :D
There is currently only one weapon in the game, and everything about it, from it's sprites to it's actual function, is currently a placeholder, which is why the item rooms don't work at the moment either. I'm planning to update the textures of that and the bullets in the future :)
Enemy designs are still kind of early, I have a few but they haven't been properly drawn or thought out, but I will try to add more interesting ones in the future.
I haven't got much in terms of story at the moment, but adding some humour is a good idea, I already have a framework for popup text so it shouldn't be too difficult to add haha.
All in all, it's still very early, but keep checking back and hopefully it'll become more like an actual game in the future:)