Seconded. We need and deserve the latest patches here. Too many companies treat non-Steam customers as an afterthought or second-class priority, but we paid as much if not more for the game here.
I know this is a publisher thing, not GOG's fault, but I strongly urge GOG to put pressure on developers like this one who ignore their platform in favour of another and thus make their whole service seem less desirable.
I totally understand that due to infrastructure, Steam will almost always get updates first; that's the price we pay for DRM-free. However, when it is weeks or even months before an update comes to GOG that has been released on Steam, it makes me very angry and feel like my business is not valued unless I buy through Steam.
If devs are going to offer their games on other services, they need to not forget about them after they've got the initial purchase!