The concept of the game is fun, and playing it isn’t so bad. My issues with it are the following:
• Unclear what coins are for. You sort of get them
But cannot spend them.
• Glitchy:
          * If you catch up to the NPC, it freezes and you can shoot it without it fighting back.
          * You can make the floor invisible by catching up to NPC
          * You can shoot from the corner of the blocks. Meaning you can shoot the NPC, but it cannot shoot you back. 
I only played around 20 levels, so I can only imagine there are a lot more issues to be found.