Unlike your common unilateral falling block games, 'Double Cross' implements
a bidirectional paradigm expanding the genre in both dimension and difficulty.

Blocks fall from the top and fly in from the side settling in a joined
"play area". Deletions occur when rows of ten blocks are completed.
A horizontal row of 10 will cause the blocks to fall down, and a vertical row
of 10 will cause the blocks to "fall" to the right.
If a vertical row is completed during a vertical drop or a horizontal row is
completed during a horizontal drop the corresponding deletion will not occur
until the next turn. This can and will lead to non-intuitive results.
Focus on the vertical alone and you will die from horizontal negligence and
vice versa.

WWW: https://code.google.com/p/double-cross/