Been playing Xenonauts and decided to post some tips I used.
Primus, Prior to Buzzard Suits, if you want to find out what's at the end of a super exposed area, have two people who can reach the end, one runs while the other runs and smokebombs if there is a threat.
Secondus, switching the first Machine Gunner and Sniper creates a high accuracy Machine Gunner that can barely move properly. Personally I love it since High Accuracy means lot's of kills.
Tertius C4 Everything prior to the Alien Space Ships that is potentialy hiding something dangerous or that let's you kill something faster.
Quadra, initially I've build strength for my troops so that they can carry 4-8 grenades + their normal loadouts.
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I love grenades.
Pentus, Aliens Can't throw grenades through doors.