Everyone's already written about the feedback, so I don't want to repeat it or write anything negative.
I'd rather say that the gun merging mechanic is truly interesting. I've launched the game about five times and I don't think I've ever gotten the same gun twice. That's cool.
IMO, it would be cool to have several guns available from the first wave so I could try merging them + there's defenetly need a some sort of tooltip with a brief description of "what to expect from a gun."
Also cool theme interpritation