Backing Every Extend Extra is the simple, addictive premise that players only have one action available to then: self-destruction. Any enemy caught within the blast radius then explodes as well, causing a chain reaction of explosions with any other craft in the vicinity. The more enemies destroyed, the more pick-ups litter the screen; pink speeding up both the music and the appearance of baddies, yellow granting more time, green more lives. Self-destruct too many times, impact one too many enemy crafts, or take too long to defeat a boss and it's game over.

Of course, setting up a big chain reaction isn't quite so simple, requiring careful patience and navigation between on-screen crafts and multitudes of bullets. And even with such simple one-action gameplay, there's still a variety of advanced techniques taught by the game's tutorial mode, including remote detonation (a la mines) and a charged, more powerful explosion.

As the stages progress, things grow even more complex. Varying visuals give each stage a unique feel. Certain objects no longer explode immediately, the chain reaction instead building inside them for a few seconds. Enemies appear faster and in greater numbers, requiring more skill to navigate through. End-level bosses become far more advanced, both in terms of size, movements, and defeat strategy, typically involving large chain reactions, which translate to big points.

However, the focus on big points and combos also represents one of the game's biggest shortcomings. Though the nine stages (seven standard, two unlockable) will take those unfamiliar with the game a few hours to work through, there simply isn't much beyond them. Boss Attack allows bosses to be battled without playing the respective stage beforehand, and players can compete for a high score on either each individual stage or the game as a whole, but there's no new content. Instead, the game's longevity relies upon the player to decide when they're tired of high score attempts, something dependent more upon the individual than the game itself.

Though short-lived, the simplicity of Every Extend Extra 's mechanics and the addictive nature thereof make for an enjoyable experience. Much like an old arcade title, most of the appeal relies wholly upon how much a player puts into it, the dearth of new content not necessarily a deal-breaker. Still, the small number of stages limits the game's overall appeal, meaning only the dedicated will find long-term enjoyment. That's not to say those focused more on levels over scores shouldn't give it a go, a carefully planned chain reaction stretching the entire screen ranks among the more satisfying moments a PSP can provide, but it's the difference between a definite purchase and a casual rental.