Most of these games were made by the company Genki around the same time: Kileak, Epidemic (which is Kileak 2 in Japan), Robotica (aka Daedalus) (co-developed w/ Micronet, but all the key staff is Genki), BRAMHA Force.
They were basically their attempts at launching first-person shooters in Japan in the mid-90s. Media.Vision of Wild ARMs fame did the same thing with Crime Crackers, though the vibe was more lighthearted, and even Jumping Flash had these sections. Basically, now that consoles could do 3D, they thought FPS might catch on in Japan, or Japanese companies could sell these games overseas. Japan had a first-person dungeon-crawler tradition since Wizardry had a fanbase there, and they like mecha more than marines and stuff, so it made sense to lump these things together.
I've played Kileak. The atmosphere is nice but the gameplay is mediocre.