A good example of how to make arcade gameplay grow up a little, "Sol Invasion" is a nifty, if unpolished, hybrid of dog fighting and RTS. Air combat has always been the slowest form of shooter, so it’s not as unnatural a combination as it might seem, and though it isn’t quite a full game, "Sol Invasion" is definitely an interesting, and surprisingly fun, experiment.
You control an interstellar combat ship, holding off endless waves of enemies trying to destroy your base. You're armed with guns, for semi-effective quick shooting, and missiles, which provide bigger bang but move slowly. Simple enough, but the enemies quickly start coming in waves much too big for you to deal with on your own, and you’ll find yourself depending on the assistance your cadre of small fighters and large fleet ships, which you can direct to target the enemy of your choice.
So half your attention is on lizard-brain dodge and shoot, while the other half is cooly allocating resources and deciding whether all hands should be attacking the big ship or divided between the enemy's main gunners and his minor nuisances. Further complicating things are the multiple upgrade paths at your disposal, by which you can enhance your allies' numbers or focus on your own weapons, as well as bring in large-but-vulnerable reinforcement dreadnoughts. It’s a striking blend of hand-eye coordination and strategy under pressure, forcing you into a really immersive state of twitch-and-ponder.
Like a lot of Xbox Live Indie Games, "Sol Invasion" is no standout in the graphics department, and the pop-gun sound effects are pretty underwhelming (though the radio voices of your allies are a nice touch). But the core gameplay is a clever next step from classic space shooters, and the mixture of brains and reflexes is surprisingly addictive.