I found the ROM online somewhere and fell in love - the soundtrack is as good as anything else on the system, and it's just a perfect little game. Happy to find it on itch to send some money.
One little thing for anyone who is having controller issues on real hardware, it probably isn't the game's fault - I'm using a Retrobit 6-button wireless pad, and I also had issues during the password screen on Red Zone. The Retrobit MD receiver needs flashing with the latest firmware, this fixed both problems.