Halo 3 ODST has sold 2 million copies in its first 24 hours. Early this week preorders for the game stood at 1.35 million in the Americas (which was lower than Halo 3’s 1.95 million), and first day sales totaled to 1.5 million in the Americas with over 500,000 worldwide. Bungie leaderboards on the first day showed 950,000 users had signed up with ODST.

ODST sales are still down 30% from the Halo 3 figures (which sold nearly 3 million its first day back 2007), which isn’t bad considering a lot of protest over the full-game price of what many players considered to be an expansion for Halo 3.

Halo 3 ODST storyline fills many gaps in the storyline of the Convenant invading Earth and the events of Halo 2 & 3. ODST stands for Orbital Drop Shock Troopers. It is considered by some to be the toughest Halo game in the series.

Halo 3 ODST comes with 2 discs, one with the game, and the other with 24 multiplayer maps. Halo 3 ODST is available for the Xbox 360.