Kyokugen Dasshutsu ADV - Zennin Shibou Desu

Virtue’s Last Reward follows the trials and tribulations of Sigma, who is drugged and kidnapped from his university. He wakes up in an elevator with a girl named Phi. After discovering they are unable to escape the elevator, a strange rabbit appears, introducing itself as “Zero III.” Zero III explains that they are about to play the “Nonary Game: Ambidex Edition,” a deadly game of life and death.
What’s in store for Sigma, Phi, and the seven others they eventually meet? Why have these nine been chosen, and most importantly, who will they ally with and who will they betray?

The game also has an adventure game sequel, "Zero Time Dilemma".