The game casts the player as a researcher at the Earthquake Institute, and his task is to visit various Zones along the California-Nevada border where upcoming earthquakes are predicted to occur. After a while, tremors occur; take the Fault Trip, which will cause California to split from Nevada, allowing the pinball to get locked. Use another ball to keep visiting more Zones, and soon a full-blown Earthshaker occurs, starting three-ball multiball.
Fittingly, Earthshaker! is the first pinball game to include a shaker motor that caused the table to vibrate during gameplay. The first 200 units even had the Earthquake Institute building sink into the playfield during multiball; however, the feature proved too costly, and was discontinued in later units, making early versions of Earthshaker! quite the collector's item.
A digital version was formerly available for The Pinball Arcade until the license to all WMS tables expired on July 1, 2018.
Earthshaker! demonstrates the following tropes:
- Anti-Frustration Features: Shooting the ball into the Shelter within 15 seconds after the end of multiball starts Aftershock, giving the player another chance to score the jackpot.
- Artistic License Geology: Borders on It Runs on Nonsensoleum. The central event of this game is a fissure hundreds of miles in length. Said fissure is precisely along the California-Nevada border's entire length. The Earthquake Institute is in charge of monitoring it rather than the US Geological Survey. Said monitoring consists mostly of driving down 99 miles of highway looking around. There are underground earthquake shelters, which makes no sense considering earthquakes originate underground.note
- Boring, but Practical: Shooting the middle ramp ad nauseam is actually a very viable strategy.
- California Collapse: Unlike many other examples of this trope, California doesn't sink into the Pacific Ocean — it just slides away from Nevada in order to allow the pinball to roll across the ensuing fissure.
- Further exaggerated on the sides of the backbox, which shows the two states jiggling away from each other.
- Cap: The counter for miles accumulated tops out at 99 miles (the playfield inserts themselves being unable to accurately show any miles past 75). Additional shots to the center ramp score an "End of the Road Bonus" for 200K.
- Earthquakes Cause Fissures: Shown on the backglass.
- Elvis Lives: Though never named as such, the man on the backglass is implied to be Elvis. This is especially evident with the original backglass art, which showed him driving a pink Cadillac.
- Excited Show Title!
- The Face of the Sun: An angry/panicking sun (with sunglasses) appears on the playfield.
- Gag Boobs: The woman on the backglass has a pair of comically unrealistic round breasts.
- Lantern Jaw of Justice: "Elvis" has one.
- Making a Spectacle of Yourself: The woman on the backglass is wearing a pair of pink, banana-shaped glasses with plastic stars on the tips.
- Outrun the Fireball: The playfield shows a female jogger frantically trying to outrun a fissure right behind her.
- Painting the Medium: The cabinet vibrates when an earthquake occurs (in the game).
- Precision F-Strike: One of the game's quotes has the woman exclaim, "Ooooh, bitchin'!" when the player gets an extra ball. This was enough for some parents to complain, and Williams provided a "family" ROM patch to operators as a result.
- Shattered World: A minor variation, with California and Nevada breaking apart from one another.
- Skill Shot: When putting a ball into play, the ball enters a spiral located in the upper left corner of the playfield. The spiral contains exits for 10K, 25K, 50K, and 100K points. A strong shot from the plunger causes an "overpass", which awards 25K points and 1 mile. The overpass directs the ball to the lower left flipper which allows the player a shot at the center ramp before the 50K timer expires.
- Title Scream: When multiball starts or balls are locked, the title is screamed and the machine shakes.
- Vanity License Plate: The pink Cadillac on the playfield has plates that read FLIP OUT.
- Visual Pun: The backglass shows a yuppie being ejected out of his car; "YUP E" is written on his tie.
- Volumetric Mouth: Shown by one guy in the playfield (near the fault area), as he gets splashed by a fire hydrant.
- Woman: "J-j-j-j-j-j-j-jackpot!"