Did you really think we were going to forget about Valve's sci-fi classic? Half-Life 2 introduced one of the sturdiest game engines of all time, surpassed its legendary predecessor in every way, and permanently raised the bar for narrative in the FPS genre. Despite being released almost ten years ago, Half-Life 2 is still a good looking game; a notable achievement for a 3D title that went straight for realism. It also featured a great physics system, which was utilised for object destruction and realism, as well as some creative puzzles. Half-Life 2's greatest strength was in how completely it managed to immerse players. Although it was a very linear campaign, players were absorbed into the organically told narrative, which was realised primarily through in-game events and background exposition. Control was given for the entirety of the game, with no cutscenes that were removed from the action, really allowing players to feel like they were Gordon Freeman himself.
