The last Metroid game was the divisive Other M released way back in 2010, making this the longest gap without a Metroid game since the franchise was rebooted with Metroid Prime and Metroid Fusion in 2002. It's safe to say that Retro Studios is likely already far into the development of a fourth Metroid Prime game, though quite what form it will take is anyone's guess. Given that 2007's Metroid Prime 3: Corruption was the last in a trilogy, it's presumed that the fourth game will kick-start a new trilogy, hopefully ignoring the unsavoury "character development" of Samus that occurred in Other M and bringing the series back to its brilliant best. The fact that the game hasn't yet been officially announced is another example of how Nintendo aren't making smart business decisions: Metroid Prime 4 should have been in development for years, ready for release shortly after the Wii U first hit stores, but realistically, it won't be with gamers until the console celebrates its third anniversary, or perhaps even later. Release Date: TBA