MY LIFE IS NOW COMPLETE.
A parody of Ib, an RPG-maker horror game, in which the main character, Ib, was trapped inside a gallery. Well, we have Sisyphus starring as Ib, Aspros as Gary, and Regulus as Mary.
Man, that game is kinda twisted for its own good.
And I just realize that final panel means “Sisyphus, all alone.”
Source: 【Ibパロ】冥王の器の作品展にて , by ハナマキ