Such a cool idea! I love the mix between Hotline Miami fast action and stealth. With some polish this could be a really fun game. And I like the mix between 3d environment and 2d characters.
Some things that could help:
- Colliders are a bit finicky, you sometimes miss the enemies for no reason. Better to have them bigger than expected rather than smaller
- You can't see the environment in the dark, making you bump into things. You should be able to visually see it while the enemies don't
- Can't tell when you will trigger enemies easily. Some cones of vision or warning states above enemies head could help you be more meticulous in planning.
- The overview camera is distracting to use. You should just be able to move the camera a bit further away with your mouse and not need a whole map to plan your next move
- And the kill animation is really long. It would probably help the pace of the game to have it slightly faster