Looks Y wo Erande Shimaimashita: Yarikondeiru Game Tensei Shita Hazu nano ni, Mijissou no Gacha de Kouryaku wo Suru Koto ni Natta Ken

Hardcore completionist x not-yet-implemented gacha system = ultra broken! OGsun, a middle-aged man obsessed with the mega hit RPG “Under The Twinkling Constellations”—that sold more than 35 million copies worldwide—, suddenly finds himself reincarnated into the world of said game. An unexpected change of appearance, gacha mechanics that weren’t even in the release and a plot that went off-route; he realizes that his mastery so far now is utterly useless…!? An unpredictable and chaotic adventure walkthrough where freedom blows past the limit!!

(Source: Pocket Magazine, translated)