The game is based on the Rampage characters. At the beginning of the game, the three characters from the original game, George, Lizzie and Ralph, are available, but more characters who appeared in other games of the series can be unlocked through the Rescue mode
The basic idea is that the player drops two colored blocks at a time to the playfield. The blocks then merge into contiguous areas. When the player drops a flashing "detoblock" of matching color to touch the area, the entire area is removed and scored. This can lead to chains and combos, which lead to higher scores.
The game includes a single- and two-player modes. The following modes are available in the single-player mode:
Clear mode - this includes various areas that need to be cleared to advance to the next level.
Puzzle mode - Similar to Clear mode, but there are only a limited number of blocks this time.
Rescue mode - A cage is added to the bottom of the playfield, and the idea is to remove the blocks on top of it before the time runs out.
Marathon mode - There's no set conditions of win, the game continues until it's impossible to keep going.
Two-player modes include Rescue mode (similar to the one-player mode), Score mode (competition for higher score) and Attack mode.
Source: Wikipedia, "Rampage Puzzle Attack", available under the CC-BY-SA License.