Cluster is one of those games that feels right.

You play it and you wonder, "Has this been done before?" not because it's unoriginal, but because it so obviously works.

I felt the same way about Super Hexagon, which Cluster takes several cues from, including its simple, color-coded style, abstract shapes, and even a voice at the end that's there to remind you again and again: "Game. Over."

Like most tough, reflex-based games, Cluster's controls are the easy part.

You use the left and right arrow keys or A and D to navigate a small triangle side to side.

Pressing both at once (either left and right arrow or A and D) activates your boosters, which allows you to burst through the pulsing square obstacles.

These give you points, which let you progress, without interruption, to new levels.

The boosters are also necessary for outrunning the flashing white wall that begins to rise up after a period of inactivity. Touching this, or any of the game's flashing white spiked squares, is a game over.

Similarly, touching the normal squares without boosters on is also a game over.

Most things in Cluster are a game over.

If you try to cheat and keep your boosters on for too long, the game will generate a white square in front of you, which can't be passed through even with boosters.

The key to getting a high score in the game is actually in its name: Cluster.

I found that aiming for clusters of squares can earn you more points with less risk than simply swerving around trying to hit them one at a time.

Cluster features music by Kozilek, who worked on the music for Wasteland Kings and Luftrausers.

You can play Cluster free on, either in a browser or a download for Windows, Mac, and Linux.