I go into GOG Galaxy, click play, the screen flashes, then nothing happens. Am I missing something?

?
You know that is very very little to go on for anyone to try to help you...

Do you meet system requirements? How about a list?
That is great place to start.

is the process running?
If not try push play again. Don't say you did actually try it you want it to work right?

Do you have a white screen with word across it?
gamepad? Hold down X
keyboard? Try holding E

Antivirus running?
Who knows you got to cover basics.

Update all drivers?
New drivers fix old problems

Drivers are up to date. I've checked that

Update
Been trying to get this to post for about an hour with no success. Had a friend look at it for me and he does think the graphics card is an issue. But he thinks he might have a spate that will work, so I will have to wait and see.

Ive got the exact same problem...
Please let me know if you have any luck dude :)

Hopefully that does the trick... let us know

Did you try restarting the computer?

So after posting this I ended up in hospital for 10 day. Only just got out. I heard there was an update that would add support for my video card. So tried it and still same result.

Well that's pretty bad luck.

Murray was actually specifically talking about intel graphics support. So presumably the opengl4.5 libraries and so on may not have to be supported at a later time. I don't think it's their main focus, though. But a lot of the resource-drain in this game comes from a sort of.. how to put it... haphazard use of filters and physics effects intended for much less populated screen contexts.

Or if you're running on some amd apu maybe, try setting the profiles manually. The amd drivers still don't really take care of any of that on auto.

Finally got it working thanks to the update supporting my video card.

I have the same issue, except that the game started and ran fine for me for six days, from launch through mid-day August 19th, and only then abruptly stopped working. The whole family was loving the game, and now my son - for whose birthday we preordered the game back in May - is gutted. I've never had a game (or indeed any software) fail to start and yet not produce any sort of feedback for the user (error message or other dialog box). Even though we played the game fine on the system for just over six days, it stopped working for no obvious reason. Nothing about the system changed, and we didn't knowingly install a patch or update. But now it doesn't start, and fails so quickly it doesn't even show up in the Task Manager. We've uninstalled and reinstalled several times over the past week, filed a service ticket with Hello Games (at the time, the tickets were in the low 29 thousands, which makes sense for such a high-profile release), restarted the system, did numerous performance checks on the system, updated drivers on everything, all to no effect. It's completely mysterious and frustrating to us.

Having heard nothing yet from Hello Games yet (they have literally thousands of other tickets to respond to first), I am encouraged to read that, for some at least, a more recent patch has helped. I will download and install that patch, and see if that helps. I still don't understand how it could run fine and then stop executing altogether, but if I can get it working again it'd be of only academic interest to me.