Sure, here is a simple text-based game using JavaScript that can be implemented as a single HTML file:
In this game, you will be prompted to enter your name and choose to play as a Crewmate or Imposter. Based on your choice, you will perform tasks as a Crewmate or eliminate crewmates as an Imposter. The game continues until either all tasks are completed (Crewmate win) or 5 crewmates are eliminated (Imposter win). After each round, you will be asked if you want to play again.