Find the following trophies in the corresponding locations:

Michigan J. Frog Trophy
In the Assembly Line Insanity level, go to where the black knights are before you trigger the switch. The trophy is located in a breakable section of wall on your way to the platform.

Porky Pig Trophy
At the end of the Muddy Evil Forest level, before you reach the Big Black Knight, get on top of one of the houses. The trophy is located in the tree top.

Road Runner Trophy
In the Pyramuddle level, get to the swinging pendulum section. Go across to the opposite side of where you entered. The trophy is located in one of the breakable boxes.

Tweetybird Trophy
In the Whack Tastic Robo Bash level, near the end is a door marked with the word "MONSTER". The trophy is above the door.

Wile E. Coyote Trophy
At the start of the Volcano Way Out level, go up the hill. Continue until you find the first tree on the left. Fall off the ledge to the left and you will see the trophy.

Yosemite Sam Trophy
In the Low Noon level, get to the part where you meet the first Big Cowboy. Go back the way you came from, past the tracks to the right. The trophy is located on top of one of the houses.

To activate infinite ammo, go the "Cheats" menu and press DOWN, LEFT, UP, RIGHT, DOWN, LEFT, UP, RIGHT, DOWN. Note that saving the game will become disabled.