Half-Life 2: Episode Two - Ambush at the White Forest Inn [Hard]
On their way to White Forest, Gordon and Alyx happen across an eerily peaceful valley, home to the long abandoned but still mostly intact White Forest Inn. However, something is off about the place, a suspicion confirmed when the Combine stage an ambush, trapping our heroes inside the Inn.
An excerpt from my full playthrough. You'll notice that I skipped the lambda cache in this map to cut down on video length, as I just wanted to showcase the ambush itself (along with the build-up).