Green Cross is a first-person shooter developed and published by Scarce Gaming for PCs on CD-ROM, and released on February 1, 1995. The plot focuses around Kaku Jonson, one of the engineers of a Hydroelectric Power Station named Michio. Kaku must fight to survive when mutated creatures infest the station, and the Hydroelectric Deployment Squad (HDS) hunt the employees.
Chapter 1 - Before the Crisis
Kaku Jonson is an engineer at the Hydroelectric Power Station/Dam, named Michio. Arriving at Michio via monorail, Kaku continues work on the Nuclear Water Treatment Machine (NWTM), which treats water via nuclear energy.
Chapter 2 - Fish out of Water
Suddenly, an octopus attaches to a scientist's head, and he starts attack the employees. Kaku starts fleeing the facility to the underground storage area.
Chapter 3 - Sitting Ducks
Kaku learns that the octopus was mutated by the Nuclear energy, which caused it to become a parasite. Parasites then start attacking on their own.
Chapter 4 - Beat Around the Bush
Kaku starts going down to the storage area from the outside, where the mutants are more vicious, due to longer exposition.
Chapter 5 - Tremors
Kaku reaches the storage area, where he gets a Nuclear Missile Launcher, and a radio. He uses the radio to get up-to-date knowledge on the new mutants and HDS, who have arrived to hunt the employees down, so that word doesn't get out about the mutants.
Chapter 6 - Dead in the Water
As Kaku arrives at the HDS supplies drop-off zone, the dropship is destroyed by a mutated Nautilus. Kaku destroys the Nautilus, and collects the supplies, which includes an electric cannon, an automatic targetic module, and a glasses cleaner, which Kaku can use to clean his glasses when he is damaged.
Chapter 7 - Escape Route
Kaku climbs up the dam, and fins a large amount of mutants and HDS Troops fighting. Kaku starts escaping, but is shot by an HDS soldier.
Chapter 8 - Down to Earth
Waking up in the abandoned facility, Kaku finds out that Morgan Michio, a previous employee, and government official, is controlling the machine, due to being angry at the employees for firing him. Kaku kills Morgan, being knocked unconscious in the process.
Kaku wakes up in the back of a van with a masked man driving. The masked man, named Iris, reveals he was the radio operator.
- Opposites Attract was a Co-op mode which used SPN to play. One player was a HDS Troop, and the other was a Michio employee. Enemies health was doubled, puzzles were changed to fit the bill, and maps were doubled in size. It was released in 1995, along with Green Cross.
- Fish Out of Water is the second expansion, which allowed players to play from a HDS Troop's standpoint. Enemies took less damage from melee weapons, puzzles required ranged weapons, and the HDS troopers were switched with Michio employees. It was released in 1996.