Not for the faint hearted (Although there is a 'slow' mode ;) )
Maneuver your way around a colored grid, attempting to match the color of the square that you're on while activating virtual bombs to beat the enemy system. The playing grid is constantly shifting its color patterns in order to catch you off-guard.
You get a title depending on how much you've progressed. There are 24 titles from "Unranked" to "Master". High-scores and other statistics are also available.
Additionally, Gridhack has some accessibility options. There is a "slow" mode which can be enabled as well as "color blind" mode to accommodate those with various forms of color blindness