E4 improves upon the previous titles by making true on the promise of the PSP E3. Mizuguchi's trademark music synesthesia style was merely cosmetic in that title, with almost no interactivity between the music and gameplay. E4 is different, however. As if taking a cue from Everyday Shooter, the explosions now add to the musical tapestry of the game, as they'll add an interesting and catchy beat to the music playing in the background. Detonating at the top of a beat will make the resulting blast even more powerful, so internalizing the music will only add to the gameplay experience.
E4 also adds a new shield system that encourages players to pick up power-ups as quickly as possible before they become vulnerable once again. The balance created by the new shield system creates a much faster-paced game than before, one where players will opt to trigger explosions more frequently -- it also makes the game a lot more accessible than the PSP title, which was somewhat notorious for its difficulty.
The new Endless mode is a great addition to the franchise, as it allows players to enjoy the simple pleasures of the gameplay without having to think too deeply. In order to extend time in Endless mode, players will still need to pick up Extend power-ups, but so long as they do, the game can continue indefinitely, perfect for competitive point earners and casual gamers alike.
It's easy to say that Every Extend Extra Extreme is an improvement for the franchise. It offers accessible gameplay that works well for both the hardcore and the casual, and includes a plethora of modes that will certainly keep players interested. The shooter mode, for example, returns the game to more traditional roots. The only misstep seems to have taken is in its visuals. Compared to the vibrant and varied themes found in E3, E4 looks somewhat uninspired. Also, the boss characters have been removed from E4. Sure, they were much too difficult in the previous game, but they could've added a lot of potential for quick strategic thinking. However, E4 is a clear progression forward for the series, one that deserves to get a bit more attention on XBLA.