I thought Space Ace was pretty cool. All three of the Don Bluth games were at least interesting and worth one playthrough in your life (or a watch on youtube). But Space Ace seemed to have the most variety in terms of environments. I actually played through about 70 percent of Time Gal a few weeks ago before I got bored and just looked the ending up on youtube. Holy fuck is that game anticlimactic. The final boss only has like 5 moves before you beat him.