Inquisitor is played with a mouse only. The goal of the game is to be the first faction to reach 3 points. Each round you will select a number of personnel required for the mission. If no assimilants are present on the away team or they choose not to act at this time the mission will be a success and you will score a point, if an assimilant is present they will often sabotage the mission and it will fail, scoring a point for the assimilants.

There are also two interrogation rounds where you can determine the faction of a single personnel. Use these carefully as attempting to identify assimilants is key!