@Cesar,
It's OK now. Setting ShowGameLauncher=0 solved the problem ! Man, I was desperate ! Thanks for the tip.

Anyways, creating a custom shortcut also works but then I would have two shortcuts pointing at the same target. Looks like {commonprograms} constant works fine.
Code:
Shortcut2={commonprograms}\Amnesia Rebirth\Play Amnesia Rebirth; Destination:{app}\AmnesiaRebirth.exe; WorkDir:{app}\; IconFile:{app}\AmnesiaRebirth.exe; IconIndex:0;
P.S. Maybe I became too old for this.