DashRiprock: Try clicking 'more'. It's next to 'play'
Select manage
select verify/repair
See if that corrects the problem.
The same problem appeared for me today , but please bear with me : Today " Vampire : The Masquerade - Bloodlines " was updated , probaly the unofficial patch latest version of it , and because I feared that there might be some problems with the unofficial patch version I had installed before , I uninstaled the game , had the remove all files option checked , I restarted the computer and then reinstalled the game . It was then that the play button problem occured for me , I verified/repaired the game ,and and launched it . It worked . So did my saves , but when I checked the save folder location which is in the game foder according to my google search , the save forder was empty . Even if my saves work , get uploaded on the cloud , and get downloaded as backups .
Oh , and I use the " 2.0.46 Beta " version of GOG GALAXY .