Super Pitfall Cheats

To get a bunch of extra lives, in the first level, go right and jump over the first waterfall and kill the frog you come to. Then, go right, down and opening in the floor, and down a ladder.
Now, go left just past the ladder, then go back right and kill a frog. Here, keep going back left and right and frogs will keep appearing. After killing 7 frogs, you'll get an extra life. Do this as many times as you want to keep getting extra lives.

Start the game as usual and go forward to the first ladder. If you jump near it, a gun will appear that will give you 20 extra bullets.