Bugfix release 1.1.3.1 is out - please get rid of 1.1.3 as soon as possible.The 1.1.3.x release post has been updated.
An original bug (sort of) which slowed down level loading, especially with vsync on, has been more or less fixed: There's a speed-up of the loading screen part of a factor 2-10 - the high end is for the menu, which now loads in less than one second on my laptop. (There's still all the exe relaunching and D3D initializing slowing down level loading, and probably nothing to do about that.)
The Steam and GOG issues should be fixed now, as well as some stupid bugs in the installer and in the patch itself. Somewhat annoying the old 'dotbug' problem has been back, probably since 1.1.1, because the fix was disabled by default.So when playing e.g. The Keeper FM on a GOG game installed to ...\GOG.com\... there would be text like 'book Metal8 not found' instead of 'Pub'. Fixed now...
I've tested this both with Steam and GOG installer versions 1.0.0.5 and 2.0.0.6. Thanks to Corsair, Lolwutman and tolsen64 for feedback and testing, and again to Lolwutman for pointing out the connection between vsync and loading times.