I am also having problem in tactical, the game always close and so as part 1 is activated.
Sat Feb 13 19:20:41 2016: Xenonauts, version .
Sat Feb 13 19:20:41 2016: Pixel Shader Version: ffff0300
Sat Feb 13 19:21:11 2016: ##### : Missing string for label 'Undefined'
Sat Feb 13 19:21:41 2016: MOD ERROR: An element to replace does not exist: Weapon
Sat Feb 13 19:21:41 2016: MOD ERROR: Merging XML for weapons_gc.xml from mod mods/choicespart1/ failed.