Dig Dug meets Collapse (review of pretty much the entire series, rather than this one game)
Original idea of Mr. Driller - putting a character from Dig Dug series inside a Collapse board.
Punishing. Poor use of the already lacking speech synthesizer of the Game Boy Advance. Missions differ only by starting backdrop and the goal mark, Very cheesy storyline (though that may be unnecessary for this kind of game, but then again - omitting it entirely would've been better)
The Bottom Line
Collapse board, with occasional clusters of hard blocks.
If a block falls, it may cling to first encountered block of same color.
Most block types are destroyed in color groups if they share borders (but not corners).
Blocks may also self-destruct upon forming a 4+ cluster dynamically (such as on player's actions or in a level with lots of hollows).
Hard blocks take a lot of air and several hits to destroy, and only get destroyed one-by-one (unless a self-destructing cluster is formed).
You can climb up one-block-tall walls, such as to get to an Air capsule.
Air limits your time, and adds a sense of urgency to gameplay.
One hit from a block, or running out of air, makes you lose one life.
Every 500 ft, a green wall is present (grey in one Flash version), and in mission mode breaking such a wall on certain depth is the win condition.