Global free-to-play games revenue saw a 6 per cent increase to $87.1 billion (S$117 billion) last year, with Epic Games' Fortnite ($1.8 billion), Nexon's Dungeon Fighter Online (1.6 billion) and Tencent's Honor of Kings ($1.6 billion) ranked in the top three spots, according to a recent report from data analytics company Nielsen's SuperData Research Group.