Not sure if this is the right place to ask, but I have a request for a feature that I think would be very helpful to a lot of people and (hopefully) not too hard to implement:

The ability to manually edit your time played for each game/executable you have linked in your GOG library.

Tracking time played works well for the most part, but there are exceptions where it does not work properly (i.e. when playing old games through separately patched .exe files). It would be very nice if we could manually fill in our time played in those cases, just so we can get a more complete and accurate account of the time we spent with the games in our library.