Arcade mode is locked to premium buyers but I got this through the Racial Justice Bundle - Are games from that bundle only demos?
Hi there! QLRZ is indeed a demo. Albeit I had high hopes for it when I published it in 2015, after developing it for almost 3 years, it never got a lot of downloads (think < 500). So Arcade mode is not locked to premium buyers, it's a feature that was on the roadmap for a future development that simply never occured.
Hope you still had fun with the part of the game that does exist!