Half-Line Miami is a free, fully playable mash-up of Hotline Miami and Half-Life 2, complete with the G-Man introduction, and it's really good.
The actual gameplay is straight out of Hotline Miami, but the maps, enemies, and sound effects are taken from Half-Life 2. And instead of the usual assortment of blunt objects and firearms, you're equipped with the gravity gun, which works exactly like it does in HL2: Pick something up—explosive barrels included—and then fire it at your enemies to turn them into pulp.
