The first game for xbox one which is coming on 1st of may all the way to the 31th is Marooners, which is a multiplayer a perfect party game to have fun with friend. 
The next game coming on xbox one is The Golf Club 2 Featuring PGA Tour which is coming on 16th May and staying June 15th.
Earth Defense Force: Insect Armageddo Will be the first game coming to xbox 360 both games for gold on 360 are backward compatible May 1 to 15 on Xbox One and Xbox 360
Comic Jumper Is also another 360 game which will be coming later on May 16 to 31 on Xbox One and Xbox 360.
