So, this guy woke up alive at the bottom of a bottomless pit, can jump 20 meters in the air... twice... without hitting the ground, and can fire bullets at a speed that might rival a modern-day machine gun... is this guy a robot ninja or something?
Really, it's pretty easy killing Tom in around 4 minutes. Before he goes skull, just try to avoid him as well as you can, scoring a hit, here and there, as to not get hit by a surprise beard attack. He alternates going from left to right on his laser attacks, so follow him and beat the crap out of him. After he goes skull, stay towards the left hand side of the screen, and only hit him while he's moving, and running like a coward when he fires. Simply put, the only real challenge in getting the hard badge is impatience and carelessness.
on the topic of mutant zombies: "Can't they find someone else to annoy? Friends? Family?... Poisonous reptiles?" (Cool points for you if you know the reference)
umm... you guys might know this already, but each bonus level is unlocked with 5 "A" or "S" rank, and they distribute ranks too. You don't have to get semi-perfect scores on every level, you just need a total of 20 to unlock the last one.
 "Boss Battle"){kind=icon}
 "How to Raise a Dragon"){kind=icon}
 "Insectonator: Zombie mode"){kind=icon}
 "Clockwords: Prelude"){kind=icon}
 "DJManiax"){kind=icon}
 "Edmus"){kind=icon}
 "Diamond Hollow"){kind=icon}
 "The Tickler"){kind=icon}
 "Book of Mages: The Dark Times"){kind=icon}
 "Castle Crashing \"The Beard\""){kind=icon}
 "Chibi Knight"){kind=icon}
 "Upgrade Complete 2"){kind=icon}
 "Road of the Dead"){kind=icon}
 "Trollface Launch"){kind=icon}
 "Castaway"){kind=icon}
 "Bullet Heaven"){kind=icon}