This was one of my favorite games of all time. The only downside was the overly long, boring cave. Let's plop you into a fast paced game in a beautiful alien world, then have half of it take place in a cave!
Flashback never did it for me. It's like they decided that the immersion and atmosphere of OotW needed to be toned back and made more like every other sidescroller.
The guy did another game called 0n Escape or something. It seemed like a cool mix of Flashback meets Bladerunner with OotW's atmosphere, but within the first 5 minutes they dump you into a cave maze and I quit.
So uhhh...ditch the caves and you'd have the best games ever.