Another one is Bonk's Adventure. It's not the greatest OST, but considering this was the best selling game for the PC-Engine, the fact that there's no soundtrack is really surprising. The tunes are pretty catchy too. I'm still hoping this will be printed someday.
If you've never heard the ending music to this game, it's quite nice. Youtube link here:
https://www.youtube.com/watch?v=2SX4...gxJW7uwhn0JXiH