XB1 games require an active Gold subscription.
360 games are backwards compatible.
Sorry this GwG post is late, it's mostly Mo, Xandler and Bardfor's faults.
June 1st:
SpeedRunners - https://www.youtube.com/watch?v=dQw4w9WgXcQ
This is an action-platformer for 1-4 players where you compete to get the best time blasting through levels. Lots of characters and weapons, cartoony visuals. Lady Evol loves this game more than her kids*.
Assassin's Creed III - https://www.youtube.com/watch?v=rbsPu1z3ugQ
Yay another Assassin's Creed game. This one is set in revolution-era America and has you fighting through snow to stop the Templar and also has an earlier, simpler version of Black Flag's naval combat. This is my least-favourite AC game, but free is free.
June 16th:
Watch_Dogs - https://www.youtube.com/watch?v=QOb6JSQd-Qw
This is an open-world action game very similar to Grand Theft Auto, except you can use your phone to hack in to all sorts of things like traffic lights, steam pipes, drones, and BoyzR's bank account.
Dragon Age: Origins - https://www.youtube.com/watch?v=KEodtWN7Xb0
This is an action RPG -- the visuals and combat aren't as smooth as later DA games but the character abilities & storytelling are better. I actually like this one a bit more than Inquisition.
Source: https://majornelson.com/2017/05/24/xbox-live-games-with-gold-for-june-2017/
*not that that is saying much...