Honestly just curious. I'm not expecting to play any of the new releases, but something that doesn't need a lot of hardware should be playable, right? (Games from the early 90's and before, visual novels, some point and clicks, etc)

No. For a few reasons.

1. Windows Phone isn't a full Windows (no desktop, all GOGs are desktop applications, not metro/"modern UI" ones).

2. Windows phones generally don't use x86-compatible CPU's (do any?). The GOG installers only run on x86 Windows, though some games are run through DOSBox and ScummVM which do run on a multitude of architectures.

3. DOSBox and ScummVM aren't available for Windows Phone as far as I know (but that's just it - as far as I know - I may be wrong), so even games already emulated on computers - using those applications - won't run (both DOSBox and ScummVM are available for Android though, if you're looking into getting another phone or tablet).