You can now play 2003 Halo 2 demo ( Full Playthrough)

The Halo 2 E3 demo was a real-time demonstration of early plans for Halo 2’s Outskirts and Metropolis levels, showcased at E3 2003. The demo featured several new designs for the game, including:

ODSTs (Orbital Drop Shock Troopers)
Semiautomatic Battle Rifles (as opposed to the three-round burst in the final product)
Dual-wielding
SMGs (Submachine Guns)
Brutes
The Gauss Warthog, a new vehicle with a Gauss Cannon mounted on the back
The demo also allowed attendees to offer suggestions on what to do, showcasing Master Chief’s ability to toss a grenade into a medical tent and kill his own wounded men. The demo’s music was recorded just two weeks before E3, featuring a 32-piece orchestra and 16-voice choir.

The recreated demo, now playable in the Master Chief Collection, remains largely faithful to the original E3 presentation, with some tweaks to gameplay mechanics to better match the original feel. This includes disabling sprint and clamber, enabling friendly collision, and increasing jump height.