The game in question being Hitman: Game of the Year Edition, which has content locked away behind an online connection. The community is not taking the news well:
https://www.gog.com/forum/general/release_hitman_game_of_the_year_edition_11093
https://www.gog.com/wishlist/games/remove_hitman_game_of_the_year_edition_from_catalog
The store page for the game currently features this lovely banner, a less than stellar user rating and a bunch of customers who are rightfully upset at the prospect.
And GOG should stick to their mission statement and not sell the game if it goes against it.