any month ago i asked the same question, but i imagine why i can´t do this...so what about? i created a blender-runtime (on windows xp) and after that, i compressed it with UPX. when i tried to start it, the console-window pops-up and shut down immediately. i had compress other executables (not blender runtimes), and it worked fine. but what´s going on with the runtimes of blender? did i compress the runtime with a wrong command, or what´s going on?
is there anybody who could help??
The blender game is the game-engine and the file glued to that.
Maybe your UPX figures out that where the program (GE) ends and regards the rest as garbage (being actualy your game).
Can you uncompress the UPX-ed file and see if it's got the same bytesize?