There are some problematic glitches I noticed, one not to bad, the other very annoying: first, if you jump on the top of the screen's edge (at the highest part of a level), you will become stuck inside the wall and have to exit the level. The more annoying problem happens if you are put against a wall by one of the big red boss-like enemies in the last few levels; no matter what you do, you're trapped, and pretty much guaranteed to die. Unless there's a big secret I missed, Level 4's Star is impossible to get, but everyone's already mentioned that. If this had a few more upgrades and maybe abilities, it would also be awesomer.
 "Robin the Archer in Pixeland"){kind=icon}
 "Flaming Zombooka"){kind=icon}
 "siftheads 5"){kind=icon}
 "Spacecraft"){kind=icon}
 "Elona Shooter"){kind=icon}