This is just patch 1.59. If you want the full game, you will need 1.51 and probably patch 1.54:
Xenonauts 1.51-GOG
Patch 1.54 Xenonauts-GOG
Dev quote:
"V1.59 is the revised version of V1.58, which we rolled back a week or so ago because we were concerned about stability issues. V1.58 included several fixes over V1.56, the biggest of which was a fix for an annoying AI hang."
V1.58 Changelog:
- Another fix to an AI hang with the Reapers
- Alien base missions should now always load correctly on the Linux version of the game
- Fixed an occasional crash related to the Fury interceptor destroying a UFO with escorts
V1.57 Changelog:
- We've created an experimental patch for the shooting code that should verify miss shots are actually able to hit the tile they scatter to. We hope this will correct the issue where shots are sometimes noclipping through walls or otherwise behaving incorrectly.
V1.56 Changelog:
- Fixed an issue with the mod manager deleting the entire mod directory when you tried to delete a mod
- Fixed an issue where the mod manager did not correctly save the priority order for deactive mods
V1.55 Changelog:
- Fixed a second AI hang that was locking the game up during the alien turn
- Updated the Carrier UFO maps to remove more areas where Harridans could fly inside the UFO walls and then snipe down at you
- A fix to the mod manager not remembering changes made to mod list priority if you exited the launcher without loading up the game
