Very simplistic yet so fun to play. If this was released in NES or Atari period it would definitely become a hit. The downsides of the game is It's difficulty, I think an increasing level of difficulty starting by maybe making the guard AI dumber at first or adjusting the camera,guard ranges or increasing the number of items in the first stages stage could work. Adding a simple background music which can be turned off optionally could also make the game more atmospheric. Overall I really liked the game,I hope you build up on the idea and make updates to it!