Tried this with both 0.28 and 0.30.
I downloaded X:CE 0.28 (and later 0.30), installed it as instructed (install using mod manager, copy executables to replace originals) and I get the X:CE version number in the launcher to indicate it's running the correct exe. However, when I try to start the game itself, there's just a brief dark flash (presumably the game window being created) and then immediately a crash with no error message.
Using 32-bit WinXP, Xenonauts 1.09.