Chain Reaction (known in Japan as Magical Drop) is a tile-matching puzzle game developed and released by Data East for arcades throughout 1995.

An adaptation of an obscure Russian DOS game called Drop-Drop, Chain Reaction is known for its cute art style (with characters based on tarot cards) and two-player competitive gameplay. Players control a little clown at the bottom of their playfields and try to arrange groups of tiles to make them disappear before a tile reaches past the bottom of the playfield. This is done by pulling down similar tiles (and throwing them back up) to match.

The game includes two game modes: the one-player score-based Solo Play (where additional lines of tiles regularly drop from the top of the screen) and two-player competitive Battle Mode (where the second player can be human or CPU opponents). Similar to Tetris Attack, players can make “chain reactions” by quickly creating near-simultaneous matches to either boost their score (in Solo Play) or fill up more of their opponent’s playfield (in Battle Mode).