Chain Reaction is a 3d action game, with slightly more coloured backgrounds than your usual isometric specimen, vaguely similar to Strike Force Cobra [Phirana, 1986], plus a black main sprite. It's not a 3d platform like Head Over Heels [Ocean Software, 1987], and neither an arcade/adventure like Fairlight [The Edge, 1985]: your aim wandering among the rooms, find the small radioactive cylinders littered around, and dispose of them letting them fall into the circular hole at the center of the structure: the cylinders, though, are distributed over several levels, and you must use elevators to move among them - the disposal operation, anyway, it's only possible at the first level - to complicate things you have three kinds of shooting guardian robots, and the obvious time limit.
You have unlimited bullets to wipe off the robots, though, and a jetpack if you want to try to hover over them, or over holes in the floor from the second level up [which are anyway very useful when you need to reach the disposal hole in the first floor very quickly]. Some of the robots are a sort of small flying pyramids with antennas, so it's particulary difficult to fly over them, although sometimes you'll find yourself standing over them. Each time the robots hit you with their bullets, the "Rad" bar decreases, so you must be careful - because you've only got one life. Anyway, luckily for you, there are anti-radioactive showers here and there, which will clean you from the radiations and restore your health.
I think it's playable, it looks good and can become quite addictive . An obscure but good game.