Just a few from my library:

Shadow Warrior
Hard Reset
Raiden
OlliOlli
Retro City
Spelunky
Alien Shooter

If GoG wants Galaxy to be a service, this should be part and parcel of it. Let's face it, Steam is their model here. The 'features' of Galaxy are still sparse. This would be a simple one to implement, and furthermore, help my supremacy in the dick measuring contests so crucial to my self esteem.

Although I agree with you, Steam took many years to become what it is today.

When it was first released it was far worse than Galaxy, however, Steam also had the luxury of no competition.