The six Gamma IV finalists are on the GDC expo floor for the next couple of days, and I've been trying these one-button beauties out to see what makes them so special.

Silent Skies by Spyeart aka Michael Todd uses a simple control mechanic. Flying a plane over a strange world, holding the button causes the vessel to fly in a anti-clockwise arc, while releasing the button turns clockwise. A combination of taps and good timing can send the plane roughly in a straight line.

There's a few levels on show here, each with its own special theme - e.g. one sees you collecting stars, while another involves a bombing run. There's also a final boss level. The mechanic works smoothly and makes for an enjoyable, if a little tame, experience.


Honeyslug's Poto & Cabenga is a really interesting concept that sounds like it shouldn't work, yet is pulled off wonderfully. When an alien rider is split up from his trusty steed, both must jump their way past a horde of enemies. Of course, both must also be controlled using one single button.

So it works like this - when the button is held down, one runs while the other walks, while the opposite happens when the button is not pressed. Also, when the button is initially hit, the guy jumps, then when the button is released, the horse jumps. Sounds incredibly confusing (and believe me, when I watched someone play it, I wondered how they were even managing it), but the enemies spawn in such a way that a pattern emerges which isn't too difficult to keep to. Very clever stuff.

4Fourths is a 4-player team game, and is probably my favourite Gamma IV winner. Created by Mikengreg, two spaceships adorn the left and right edge of the screen, with a player controlling each (tapping the button boosts the ship up the screen, while releasing it lets the ship fall slowly down). The other two players control the guns, which are both facing into the centre of the level.

Huge boss ships are then sent one by one down the centre of the screen, and the 4 players work together to take each out. Being on opposite sides of the action, it is possible to shoot your team-mates and kill them, so careful blasting is necessary. Of course, you'll probably want to shoot your team-mates anyway since, let's face it, killing each other is fun. Mikengreg are looking for someone to help them take the idea to the next stage, so if you're a publisher-type person reading this - make this happen please.

B.U.T.T.O.N (Brutally Unfair Tactics Totally OK Now) is another multiplayer one-button experience, although it seems a rather strange choice for a winner. Tasks pop up on the screen, such as 'Think of your favourite colour' and 'Take 5 steps back', and each player must follow the rules correctly to win.

Each game inevitably ends with all 4 players rushing at the screen and bashing their (or other players') buttons to succeed. It is good fun (I can imagine a small helping of alcohol would make it a party favourite), yet it's not exactly what I would class as an 'accessible' game.

cactus' GAMMA IV - THE GAME is trippy yet simple. Lines explode out from the centre of the screen, and each tap of the button causes the lines to change direction by 90degrees clockwise. The task is to smash into each of the squares around the screen and not bump into walls and the like.

It's mesmerizing stuff, although once you realise that it's possible to simply watch one corner of the screen it does pretty much become an extravagant game of Snake.

Finally, Steph Thirion's Faraway features perhaps the most innovative one-button mechanic of the six winners. Players control a shooting star which is flying through space. Holding down the button causes the comet to use the nearest star as a centre of gravity, allowing it to orbit around, changing its direction and velocity.

The key is to find special areas in space when constellations can be produced. Once such an area is entered, the key is to loop around stars, connecting them up and creating as complex a constellation as possible. Better connections give more score and add time to your clock - running out of time ends the game. It's a really gorgeous idea, although I was admittedly terrible at it.

So, these were the 6 winners chosen from over 150 submissions. If you're down at GDC in San Francisco, they'll all be available to play on the expo floor until Saturday evening. Well worth checking out.