Played for a few hours and I enjoy they game so far!
I may have selected a too low difficulty for my first endless and I reached wave 255+. I noticed that the wave counter wraps at 256, see screenshot https://imgur.com/a/088DXdU showing 251/4 Waves.
As far as I could tell this has no detrimental effect to the gameplay, but I have yet to finish it so I can't be sure. For now I saved it and I will probably continue later.
Please note this was on Feb 2nd, I came across the screenshot just now and remembered I wanted to report it.