You are wrong about this in a fairly funny way. The code for this one is mostly copied from a game from another creator. So no, they don't actually share almost any code.
To be fair, for a "0.03 demo" - who really cares. Lots of software is started by taking another piece of software from someone else as a base and then slowly morphing it into something different by changing one piece at a time. I hope this is what the developer is doing here and they don't plan to keep it looking exactly the same as The Fixer forever. Lots of people do this, but most projects don't see the light of day at this early of a stage, which is why it's so obvious here.