Xbox Wire just gave us the run down on Games with Gold for May, taking the program past its 1 year anniversary.
Xbox One owners will get their hands on the tower-defence hybrid - CastleStorm: Definitive Edition, and can continue to download April's Pool Nation FX for free throughout May.
Xbox 360 owners can look forward to the action shooter Mafia II, in addition to Codermasters' racing sim F1 2013.
CastleStorm: Definitive Edition for Xbox One
Knights battle Vikings in this genre defying 2.5D castle-smash 'em up for Xbox One.
...CastleStorm features a story-driven solo campaign, a custom castle editor, online multiplayer, co-op modes, and more. Building castles and knocking them down has never been so much fun! CastleStorm Definitive Edition includes the original campaign and 2 additional expansions: From Outcast to Savior and The Warrior Queen. New features include: - 20 new single player battles - 4 new extreme survival battles - 10 new magic spells - enhanced graphics: real time shadows, advanced particles, 1080p@60fps + 4x MSAA - Full screen split-screen mode...
Regarding Xbox 360's Games with Gold - Mafia II will be available for the first half of May, followed by F1 2013 in the second. The photorealistic Pool Nation FX will continue to be free for Xbox One owners throughout, following on from its April tenure.
I wouldn't call May's offering particularly notable, but hey, it's hard to complain about free stuff. Keep these download links handy for future reference.
CastleStorm: Definitive Edition ($14.99 ERP) Available throughout May on Xbox One
Mafia II ($19.99 ERP) Available through May 1st to 15th on Xbox 360.
F1 2013 ($49.99 ERP): Available through May 16th to May 31st on Xbox 360.
Source: Xbox Wire