Several new website domains have been registered, but aren't online yet. The domains were registered by Microsoft, and they appear to be stores of some sort for Halo 4 or the Halo franchise altogether. If you're interested in this sort of thing, I listed the Whois below.
The websites aren't live yet, so attempting to go to them will result in a redirect by Microsoft servers to Bing.
---Halo 4 "Haven" Map WalkthroughHaven is a multiplayer map in Halo 4 that rests high above Requiem's surface. Harmonic-resonance platforms appear to facilitate the monitoring and management of the shield world's solar preservation system. These elaborate machines enable artificial planets to support their immense populations of indigenous life.Halo 4 "Abandon" Map WalkthroughOn the remote world of Erebus VII, at the very edge of human-occupied space, an ONI research facility which was once teaming with researchers now lies eerily vacant. Although the hostility of this world had been initially considered by its team leaders, it is tragically clear that a great many ‘things’ had simply not been taken into account.
Abandon is a mysteriously abandoned ONI research station on a hostile alien planet. Initial surveys of this area were bold and promising, but it quickly became clear that these reports were far more hubris than logic.
A new map Meltdown
was shown in screenshots: While most Forerunner technology appears to support safe usage over immense passages of time, the failure of specific systems can cause a cascading effect which dramatically impacts a site’s foundational composition. This frigid moon’s icy conditions once served to control a Forerunner reactor’s intense heat, but those days are now long gone.
Here's an image, showcasing the evolution of the Master Chief. As the video game industry advances, so does it's technology, thus creating more "impressive" graphics.
An overview concept of the Mantis. The Mantis mecha was inspired by the prototype mech from Halo: Legends
Halo 4 will feature the return of skull collecting. Modifying gameplay and multiplying difficulty, the Skulls in Halo 4 will behave like the ones you already know and love from Halo: Reach. In Halo 4, they will be available in Campaign and are automatically unlocked from the start.Famine - Weapons drop much less ammo.
Tilt - Enemy resistances and weaknesses are increased.
Mythic - Enemies have increased health.
Catch - Enemies are grenade happy!
Black Eye - Shields don't recharge unless you melee enemies.
Tough Luck - Enemies always go berserk, always dive out of the way, and never flee.
Iron - Co-op: Back to previous checkpoint on death. Solo: Restart mission on death.
Thunderstorm - Major upgrade to the capabilities of enemies.
Cloud - Motion sensor is disabled.
Cowbell - Acceleration from explosions is increased.
IWHBYD - Rare combat dialogue becomes more common.
Grunt Birthday Party - Headshot a Grunt, HAPPY BOOM TIME!
Blind - The HUD and the first person arms and weapon are hidden.