I actually picked up a Sinbad since this thread started. It plays very similar (an early System1) and I was going to sell it but man, it really is a difficult drop target shooters game with great rules. Now, I don't know if I really want to let it go.

Honestly, you have realized the top secret fact about all expensive collectibles... if you plan on getting your money out of a restoration, you are in the hobby for the wrong reasons. Some games were not meant to be restored to "like new" condition.