Thanatos

Thanatos is an Adventure game, developed and published by Birdy Soft, which was released in Japan in 1991. You're a private detective yourself. One day you're shocked to read in an article that your colleague was shot with a swarm of bullets. Once you set on a trail you get a floppy disk that contains information on a trading company that operates secret medicine "Thanatos" that gives abnormous strength. Setting is science fiction in the near future. It's an action story with gunfire and brawling. But there is quite little information on the game because of one reason. Game is shipped with multiple floppy disks and literally for every background or event game asks you to insert the needed diskette, then after it's seen, need to change back to original one.