How many Resident Evil games have there been? If you take into account the main cannon, plus all the offshoots and then the remakes - too many to really care about. One co-op version of the game was Resident Evil: Revelations and its being relaunched again; this time for the Xbox One and PlayStation 4.
The original version of the game came out back in 2012 on the 3DS only for it to get a HD update for the then current consoles and PC. The game offers 2 player online co-op and there is no news yet whether this is the HD version released again or a mega HD HD version:
The game's co-op mode back in 2013 had a little to be desired. To find out more check out the Co-Optimus review from back in the day. Perhaps Capcom will develop the co-op this time round?