The lack of ability to purchase ammo once you've got over 500 rounds is frustrating, since in the later levels you need the weapons that consume ammo so quickly that you can't really maintain it.
The point value needs to not immediately drop from 5 to 2 in order to make this game not a pain in the posterior. That it does means even in the levels where you don't need a perfect score, you need to get pretty much all the points in the first burn anyway.
It's not just a Greek myth, I've seen a Native American version as well. Granted, Coyote doesn't go to the underworld and have to pass Cerberus, but it's the same story: a man loses his wife and travels to the land of the dead to get her back, and after reaching the land of the dead, she is allowed to follow him out, but with the admonish that if he turns around before they get home, she will disappear again forever, and ultimately he is unable to resist the temptation.
 "Penguinz"){kind=icon}
 "Actionscript?!?!?!?"){kind=icon}
 "You Have To Defecate Upon King Bhumibol"){kind=icon}
 "Chain of Fire"){kind=icon}
 "Don't Look Back"){kind=icon}