Microsoft opened its E3 2012 press briefing with a live gameplay demo of Halo 4. Finally, that demo is available for you to see all over again. 343's Halo 4 demo featured a slew of new enemy types, along with Forerunner-based weaponry. Other additions include Master Chief's ability to switch visor modes to an infrared mode to scan the area featured in the demo.
The demo was impressive, looking like it mixed the styles of Halo and Metroid Prime. Halo 4 launches on November 6, 2012.
A new trailer is also available after the break.