Incredible. This game ran flawlessly on the FPGBC and Gameboy Pocket. The game loop is addicting and the combo system really kept me chasing that dragon. This game being more "pick up and play" will keep me coming back to it time and time again.
I really liked the use of tile swapping for the background and found the overall presentation to be very polished. I could see this being released back in the day as an arcade port of sorts on the original GameBoy DMG.
Your commitment to open source is great to see and this being written in assembly within the time frame is insanity.
Also the music absolutely SLAPS, hope to see more GameBoy games from you in the future!