Ousama Game, Torikago no Tsugai Recommendations
Both manga focus on a group of teenage school students who end up playing a twisted game with their lives at the stake, and must uncover the secret behind it before they are all killed. While the details of the death games are a bit different, both manga have a similar vibe, as well as similar art and characters.
A bunch of high school students are forced to follow dangerous tasks in order to come out alive of this life and death game that they have suddenly become a part of. The MC is of course the one who is the smartest/most hard working among all the characters, and it's thanks to him that we're able to solve the mystery and unmask the mastermind behind the entire game.