If nothing else, Xbox Live Arcade has proved that there are plenty of different ways to make a dual joystick shooter. You can go the old arcade route with something like Robotron, you can make it into a more scrolling adventure, like Assault Heroes, or you can make it, well, something in-between. Mutant Storm Empire is something in-between those two things, following up on Mutant Storm Reloaded by keeping some of the same sort of visual style while making dramatic changes to the gameplay and setting. But look, by now you've probably already decided that you're totally into these types of games or that you couldn't care less about them. Mutant Storm Empire is a good one, but it's not going to change your mind about the genre either way.
Rather than locking you into one arena or automatically moving from level to level as the previous Mutant Storm did, Empire's four worlds are broken up into four levels, many of which are broken up into multiple stages. Each stage is a room of a different size and shape, with different types of enemies in each one. When you clear a room, a door opens and you can move on to the next. As enemies shoot or run into you, your life drops. If you run out of life points, the game ends. You're also given a super attack, and it works differently from most games in the genre. Rather than acting as a screen-clearing smart bomb, holding either trigger pumps up your normal shots when you hold it down, making them more damaging and much more effective. But this also drains a meter, and when it's empty, you're stuck with your regular fire until you get to the next level.
Mutant Storm Empire mixes things up nicely because each world has a different visual style and significantly different enemies. For example, the second world has an underwater look to it. In this world, you fight shelled sea creatures, swarms of colored fish, and so on. Some levels have you travelling along a track, locked into a specific section of the screen while enemies scroll your way. The different enemies factor into the scoring as well. A counter at the top of the screen keeps track of your "beastie combos." If you kill enough of the same creature in a row, you get a score bonus. Some of these can be pretty easy, but trying to take out multiple cannons while not shooting down the rockets they fire at you provides a tricky twist to the game.
The game offers two-player simultaneous play, both locally and over Xbox Live. When playing with a partner, your scores are combined, but you're also shown individual scores and multipliers, giving you a reason to out-shoot your companion. This mode appears to work just fine, though some occasional bursts of lag can make bullet dodging nearly impossible.
PomPom's Mutant Storm Empire is a healthy upgrade over its last Mutant Storm game, but with the number of dual joystick shooters on Xbox Live nearing double digits, it's getting harder and harder to rise above the pack. If you're an aficionado when it comes to using the left stick to move and the right one to shoot, you'll definitely enjoy this quality entry. But at $10, it's a bit of a tough sell to anyone else.