I should mention that I played a version some time ago, I don't know if there has been any update in the meantime. The game is quite difficult, which is not necessarily a bad thing.
But if we talk about graphics, let's try to set some (hopefully) fairly objective parameters.
- Characters: squared and without animation. I happened once to confuse two of them in the tutorial, and only after killing one did I realised it was another one I had to kill (if I remember correctly it was said by the game itself, which I consider a good thing). But for the robot tutorial I'd put a letter on the head or something, to maybe help colour-blind people.
- Map: the rooms stand out, but I'd put something for the outside too, maybe even picking up the graphic style of the interior rooms, so as to give a little more context to the house/place. The best would be if it changed according to the map.
- Interacting elements: I mean weapons, cash and various objects. These are nice. Perhaps one could aim for something more like pixel art? Decide on a style that is the same for the map, the characters, and the weapons.
- HUD: minimal and functional, does the job. To make it a little more appealing next to the action options you could think about putting a small icon.
P.S. I played without sound, I can't evaluate music and sound effects.
GG!