Why Darwin Project and Lost Reavers are similar

Free-to-play (F2P or FtP) video games, also known as free-to-start, are games that give players access to a significant portion of their content without paying. Required before using a service for the first time. Wikipedia

Game engine developed by Epic Games, first showcased in the 1998 first-person shooter game Unreal. Although initially developed for first-person shooters, it has been successfully used in a variety of other genres, including platformers, fighting games, MMORPGs, and other RPGs. Wikipedia

Video game in which more than one person can play in the same game environment at the same time, either locally or online over the internet (e.g. World of Warcraft, Call of Duty). Multiplayer games usually require players to share the resources of a single game system or use networking technology to play together over a greater distance; players may compete against one or more human contestants, work cooperatively with a human partner to achieve a common goal, supervise other players' activity, co-op. Wikipedia