- texture coords of floor walls should start from the floor?
- port to GB Meta
- custom font
- GUI
- menu
- sounds (music?)
- level 2D map (with revealing, bitmap), special key for quick displaying map
- save/load (optional)
- enemies
- weapons
- more levels
- disable transparency for walls for performance (setting)?
- replace textures in distace with constant color for performance (setting)?
- add time slowdown constant