Atani Software released the game Chain Reaction in 2005. Originally submitted as part of The GOAT Store contest, Chain Reaction was released by Atani Software as part of a compilation Sega Dreamcast CD in 2005. It is a puzzle game in the vintage BBS-style tradition. It is a straight clone of the puzzle mini-game BeJeweled, one of the most beloved BBS games of all time.
Atani Software later released an updated version of Chain Reaction that fixed bugs in the original code. Unlike other Atani Software puzzle games like Copper Swapper, Chain Reaction is much bigger in scope and contains more gameplay.
Another big difference between the two games is that Chain Reaction uses a standard Bejeweled-style engine, allowing for a more complex game as compared to Copper Swapper. Games like Chain Reaction eventually led to the game Candy Crush and have become the most popular games on Facebook and mobile platforms.
The original Chain Reaction puzzle game by Atani Software should not be confused with the multi-player game of the same name that was developed and released in 2012.