Costume Quest 2 and Peggle lead the May line-up of Microsoft's Games with Gold program.
From May 1 -31, tower defense game Defense Grid 2 will be available on Xbox One and starting May 16, Costume Quest 2 will be available on Xbox One through June 15. When Costume Quest came out in 2014, IGN gave it a 7.6, saying its "combat and story are both surprisingly good for an RPG that concludes in roughly a half-dozen hours." Additionally, Sunset Overdrive by Insomniac Games is still available through May 15.
On the Xbox 360, racing game GRID 2 from Codemasters will be available from May 1 - 15 before puzzler Peggle takes over from May 16 - 31. Both games are also available on the Xbox One through the backwards compatibility program.