Crossplay

Is Half-Life 2: DownFall crossplay?

Half-Life 2: DownFall is only released on one platform, so there is nothing to cross-play with.

DownFall is a Half-Life 2 single-player mod taking place in the White Forest surroundings. You're once more putting on the HEV suit as Gordon Freeman. Your mission is to recover a newly developed technology by the resistance, known as the "citadel buster", before the Combine manage to destroy it.