Pause the game and enter the following codes to play as another character.
Play in Peoria and wait until the mothership arrives after you collect $2.00. Do not destroy the mothership. After its three laser shots, it will throw skulls and the occasional egg. Kill the eggs with the skulls and collect the coins. You can also throw the skulls under the laser shots to make coins appear. This will require some time, but will be easier than to play through the entire level. The mothership is not dangerous due to its slow speed. Just reach it with all three lives.
Rare aliens will only appear in Deluxe mode. They will hatch from black-and-white eggs and run very fast. They will die when they touch the lava. You must be ready to kill them the moment they pop out. Having a Woah block ready to use makes this easier.
Oddly-colored UFOs will sometimes appear in Deluxe mode. Destroy one, then board the empty UFO and fly around.
In Deluxe mode, collect $2.00 to have a mothership Boss appear. To defeat it, wait until it shoots skulls out, then throw the skulls back to the ship while it is still open. To make this easier, destroy all the enemies before the Boss appears. Normal items will stop appearing during the Boss fight, making it difficult to remain alive if you are still being chased by enemies. Defeating the Boss will reward you with a rare "Dave" block, which will not only kill all enemies but also raise the destroyed platforms back into place.
Play under the Bonkers difficulty setting to have UFOs appear very often. Hold a Woah block and stand underneath a UFO when it is about to fire.
Pause game play, then press Y(2), X, Y, A.