Choujigen Game Neptune of the Nightmare?

Neptune here! I got an invitation from Veil so I've come to Resort Island! But why is it so cold? That's no problem, really. After all, this is the beta test of a zombie game on a virtual game console so advanced, you can turn the whole island into eternal summer with just one button! But during the game, I got a report that zombies are spawning all over the world!

(Source: MF Bunko J, translated)