Achievements
Braindeath - Unlock Zombieville.
Environmentally Friendly - Unlock Enviro-Bear.
Hardgore - Unlock Sensei Evan.
Hooked - Unlock Hook Champ.
I Don't Remember This Forest - Unlock Jerry Gore.
Lizardous - Unlock Sway's Lizzy.
Merry Christmas - Unlock Xmas Gore.
Minigore Supporter - Get the character pack containing Gangster Gore and Kid Gore.
Stealthy Moves - Unlock Sway's Ninja Man.
Theme Collector - Get the holiday-themed character pack containing Santa.
What's My Tagline? - Unlock Evan Hsu.
Unlock Insane Mode
After starting the level, Run to the North-West portion of the map and stand in the circle with the X in it for a few seconds. This will spawn a skull, touching the skull will trigger Insane Mode.