There are three things that distinguish Bullethead from the hundreds of other similar, Space Invaders styled vertical shooters. Number one, it's by Nitrome, so you know it will be a high-production affair, with happy music and sound, and cute, colorful, pixelated artwork. The cuteness here is leavened with equal parts of weird-osity. You control a colorful anthropomorphic blob with an artillery cannon attached to his helmet, as you might expect. The [arrow] keys move, [<] shoots, and [>] jumps, though these controls are configurable. You strafe about the apocalyptic ruins of your home world as you fend off the descending hosts of alien invaders, who seem to favor jury-rigged, gunmetal gray ships and cybernetics, and a generally squishy appearance.
Number two, the variety and inventiveness of the enemy design. This style of shooter is so well tread that true originality is a far-fetched goal, but there were things in Bullethead I had never seen before, such as the critter who drops what I'm going to call the Doom Refrigerator of Extreme Inconvenience That Possibly Also Crushes You. My other favorites include the Death-Star-like vessel and the tiny, gibbering aliens contained within, and the slimy, bouncy, purple critters, possibly best described as Spheroids.
Number three, multiplayer mode. Yes, if you can crowd around your keyboard, you and a friend can play Bullethead together. Default controls for Player 2 are [WASD], [G] to shoot, [H] to jump. It's pretty much just twice the firepower in the same game, but there is something fun about playing with a good friend and yelling at them about what a hapless bungler they are, and hearing the same from them, and hey, that was my power-up, you already got multi-shot! Yeah, well you snagged that shield from me when you were already shielded up! As if such a degree of camaraderie and good feeling was insufficient, you can even give up one of your lives to resurrect a fallen comrade by standing over him and pressing the [down] arrow, leveling the disparity between player skill. Unfortunately all this activity on the screen does make the game lag a bit.
Bullethead is not rife with originality, but it's a well-implemented example of a familiar genre. Clever enemy design and Nitrome's signature style make it a worthy entry.