Much like its inspiration X-COM: UFO Defense, the game involves running an international alien defense system. Half of the game takes place in real-time on a global map, divided into regions that provide funding to your operation based on how effective you are at providing defense. You can place bases around the world and add radar stations, hangars for fighter jets, laboratories for research, workshops for building new items, medical centers for rehealing, and garages for vehicles. Once a UFO is sighted, you can send a number of jets towards them. The controls for the air battles are cumbersome and inexact; simply autoresolving battles is usually a better option. Once a UFO is shot down, you can call in an airstrike or take your team for a tactical battle. The turn-based battles has you exploring a handful of different semi-randomized environments for the downed UFO and any aliens that might be along the way. Movement points can be used to shoot, toss grenades, heal, or reaction fire during the alien turn. Spotting aliens and preserving line of sight is important for victory, although losses are inevitable. The tactical battles are challenging, but more because your units usually die in only one shot rather than advanced AI: some enemies wander around aimlessly or simply hide in the UFO, waiting for you to smoke and grenade them. In the end, Xenonauts is an addictive remake hindered a bit by occasionally pedestrian AI.