Bart wakes up in the middle of the night and sees a UFO. He is the only one that knows about the alien invasion. Hence, he starts a journey to stop Aliens' evil plans and defend the earth. Although, this is the first Simpsons game, the plot has little to do with the show's material. Regardless, many of the show's characters make an appearance.
In each level, Bart is faced with various objectives that he has to accomplish and certain items that he has to collect before proceeding to the level boss. These objectives vary in each level, and most of them reflect Bart's personality in the show.
Bart can activate X-Ray vision to identify humans who have been abducted by aliens. By jumping on them, Bart can collect letters that form the name of the level assistant. If he forms the whole name, then that character will provide assistance in fighting the level's boss. For instance, in the first level, if Bart collects all the letters of "Maggie", she will help him fight Nelson, the level's boss, by throwing Bowling balls.
There are various items that Bart can buy and use as weapons or to cause a special event. These items include Slingshots, Sprays, Rockets, Whistles, Magnets, Coins, etc. Some of the items are used in many clever ways. For instance, if players blow the whistle in front of the retirement home, Grandpa Simpson will come out and start throwing money.
The game is considered to be very difficult. The lack of saves, continues, or check points increase the game's challenge. In addition, for each life, Bart can only be hit two times before dying; players only start with three lives. Finally, most of the enemies can only be avoided, not killed.
There are numerous small additions and details added to the game; for example, in the third level (The Carnival), Players can take part in most of the carnival activities. Players can even buy a magnet and use it to cheat in the "spin the wheel" minigame.
- Location: Power Plant
- Helper: Maggie, Marge, Lisa, and Homer
- No Boss