Evil Under The Sun features Hercule Poirot as the protagonist, unlike the previous game in the series, Agatha Christie: Murder on the Orient Express, which had featured Poirot as a non-playable character. It also features numerous improvements and expanded gameplay elements, with a new inventory system, dialogue choices, and more environments. While players take the role of Poirot, they are actually playing as Captain Hastings playing as Poirot, in an interactive scenario designed by Poirot in order to allow his long-time friend a chance to solve the mystery in the way Poirot would.