The actual storyline within the game is based around the initial drop and how it manages to go tits up based on the actions of the new team leader "Dare", who is the "TROUBLED PAST WITH ANOTHER GUY IN THE TEAM" chick, who is blatantly going to cause problems for that team member when the most awkward time slot appears. After the initial drop, you are left scattered from your team in the city below after a Covenant battleship goes to warp, primarily fucking up everything for everyone. After quite an awesome intro, you're left to walk around the ruined city looking for clues and hints as to what the fuck just happened - And possibly "Where's Adam Baldwin? I bet he's doing something fucking awesome right now" You'd be correct in this presumption.You pass through different ODSTs within the game, discovering different parts of the story and placing together pieces of the puzzle. But the one problem I found with the story was a lack of depth, I didn't feel enticed by the story like I should have done, not that the other Halo games have indepth stories, but they have enough story to keep me interested for extended periods of time, it was like the story didn't fit in with the Halo universe or like they figured less important characters of the Halo Universe didn't get as much plot depth.
Whilst this may seem like a little issue, I found that the Co-op within the game was frustrating, whilst the actual gameplay is fine, it actually frustrated me that they didn't implement Co-op characters into the game, which felt like a big step down from Halo 3's Arbiter and Master Chief thing that it had going on. I played through with my friend and it appears that Player one plays as what ever ODST you're playing as in the plot, whilst player 2 gets stuck with a basic Rookie; Which to start with makes sense as there aren't enough characters for player 2 to play as, but later in the game you get other characters travelling with you, but these are still controlled by AI, like I said, only a small problem.
Firefight mode is pretty much horde mode from Gears Of War; Which whilst fun - Is nothing in comparison to story mode, but none the less, it is a nice addition to what the game offers; In context of nice things that Halo 3 ODST offers, I'd like to throw out there the Halo 3 Multiplayer disk that comes with the game, which is fairly immense as it not only allows you to play Halo 3 online (If you didn't already have Halo 3) but it also gives you all Halo 3 DLC, which allows you to play online with everyone on every map, it also allows you into features such as theater and forge mode.
For those who have never played Halo 3 online; You have missed out - Whilst alot of people will slate and complain about the game, I always found it entertaining, especially with friends. The amount of hours of fun you can have with it is amazing, whether matchmaking; in which you randomly search for other players online at that current time to play a specific game type. Or of course on custom games, where you choose your map, friends, game type and play how ever you like - I personally found many hours of entertainment within the Zombie game type, in which you get a group of people, with one infected, the others have to escape the infected person who can only infect people by killing them. Generally speaking the first infected; Also known as the Alpha zombie has extra powers, such as higher jumps, more health or speed boasts. The game ends when everyone is infected or the time runs out, usually the person with the most kills is the winner.
In conclusion, I really recommend Halo 3 ODST to any fans of the series; That is if you haven't already picked it up - I also recommend this to any FPS fans in general, no matter how much you hate Halo 3, allow your mind to exclude Master Chief from this experience and merely enjoy it as "Halo; The Adam Baldwin experience"...Oh and the story mode is worth the few hours you'll get out of it, especially if you're like me and you enjoy wasting an entire night with a friend to complete Co-op FPS's.