"The game board is comprised uniquely of four quadrants, each containing four tiles.
Use arrow keys to move to a random tile on the corresponding quadrant. You can explore a quadrant further by pressing that direction again - until there are no more tiles to explore.
When you leave a quadrant, it's replaced by a new random one.
The difficulty of the game ramps up according to how many quadrants you've visited." - Author's description
Play here (Browser)