A Nightmare on Sesame St.

Level Skip:
Each level is brought to you by the letter A, E, I, O,
or U. At the title screen, press A for level 1, E for
level 2, I for level 3, O for level 4, and U for level 5.

Secret Level:
Don't forget, the letter Y is sometimes a vowel. At the
title screen, press Y for a secret level dedicated to
BieberSoft's WonderDweeb.

Second Weapon:
This is more of a glitch than a cheat. When playing a one
player game with a joystick, press player 2's button #2
(Ctrl is the default) and a second stationary weapon will
appear in the middle of the screen. To cycle through the
weapons, press player 2's button #2.

Control Both Characters:
Also a glitch. At the start screen, press Ctrl-Y and
set the controls for both players the same (i.e. have
both of them use Joystick 1) then start a two player
game. You can now control both Ernie and Bert with one