Very nice port (probably the best ever)! But... I think it can be better with a few adjustments:
1. improve inertia when jumping and leaving the joystick (arcade still had a few inertia, this port does not and Wonderboy falls vertically)
2. still a bit too floaty jump fall...
2. the fairy invincibility bonus is too short (in the arcade you are invincible even after ~1 sec she leaves the screen)
this is my constructive report ;-)