The Halo 5: Guardians online multiplayer beta opened up over Christmas. No biggie, it's just the first truly new Halo experience for Xbox One.
Spread over a small selection of game types and maps, the Guardians beta brings the most significant changes to Halo's play since jetpacks and sprinting were introduced in 2010's Halo: Reach. Guardians takes propulsion power further with an always-available, rechargeable thruster pack which adds extra oomph to your play, with baseball slides, NRL-style shoulder charges, and a Mario-style ground-pound ability.
Sprinting has become an always-on feature, but it comes at a price as the same energy that powers it also powers your shield recharge. When you're choosing flight over fight, you'll have to slow down if you want to restore your health.
As fish evolved and learned to climb trees (er, as I understand it) the Spartans of the Halo universe learned to climb, and whacking the jump button near an accessible ledge will have your avatar cutting new paths and finding new sniper nests.
There are more in-game medals, for almost everything you do, and once you figure out what they're being awarded for, they help you understand and shape your play. Even better is the combat dialogue, with all of your teammates' avatars automatically shouting praise, tactics, and warnings. Better that than another homophobic slur or mum joke.