Level design was great! Some levels made you slowlyy mover forward and othre had you fight cool bosses in pretty large open areas. My favorite fights are the one against the three scorpion bat things on the sand planet and the one against the big eye. The battle with the eye has a really catchy toon!
The games pretty tough to beat though, i didnt beat it until about 2 years ago and i had it for about 5 or 6 years!
This game is one you should try!