Chain Reaction, not to be confused with several other games with that title, is a 2.5D physics-puzzle game developed by Monster Studios and published digitally by GarageGames for the PC on December 5, 2002. It also received a retail release by eGames on June 17, 2003 as Gadgets.
One of the earliest game releases by both Monster Studios and GarageGames (both formed by members of Dynamix) and an early use of the Torque Game Engine (which is built on the game engine used in Dynamix's Tribes 2), Chain Reaction is a 3D spiritual successor to the Dynamix game series The Incredible Machine.
In Chain Reaction, players must place and connect various objects, then set off the contraption so that the rocket-riding MC Monster gets pushed to his landing pad. Despite using 3D graphics, all of the physics are in 2D (similar to the games it's based on).