I love the Halo series, and I bought Crackdown explicitly to get my hands on the Halo 3 beta. I have to tell you, the Halo 3 beta is a ton of fun!
First, I have to say that it's amazing how "spoiled" we are getting by good graphics. The Halo 3 graphics really are quite lovely. The shiny metallic textures in particular look quite impressive. There are tropical landscapes, snowy drafts, and much more. But after having played a number of other games on the XBox 360 and PS3, they aren't "amazing" any more. They look great - but they look about normal for modern games. I guess that's the price you pay when you come out after launch. People are no longer wowed by what you offer.
The beta contains several different multiplayer maps with the standard types of games - king of the hill, deathmatch, grab-the-ball and so on. They are all quite fun. In addition to the classic collection of weapons (I love the needler) there are a few new additions. I like the shield ball - it creates a temporary sphere-shaped shield all around you. Nobody can shoot in. You can pop out, fire off a few rounds, and then pop back into the shield again. The problem is, someone else can pop in, drop a hand grenade and pop out. The grenade's blast is nicely contained by the shield :)
Another fun item is the portable grav lift. This shoots you high up into the air. The trick here is to hide the grav lift right in front of a much-wanted weapon. People will go sprinting towards the grav lift, intent on getting there safely - and just before they reach it, WHOOOOOSH they are launched. It turned the game into a fun skeet shoot. You sit nearby, wait for them to go sailing into the air, and then blast away.
Time will only tell if the actual storyline and plot are engaging. I can only hope this game has an "ending". It was very frustrating at the end of 2 that it didn't feel like you'd accomplished anything - you felt like you were stopped part-way through a story. I hate movies and games that end that way. Give us some closure! Let us feel at least temporarily like we've accomplished something! It would be nice if Halo 3 gave that to us :) I'm not saying that there can't be a Halo 4. There can always be sequels. They just start where the previous one finished. So finish, already! :)
Say hello if you're playing the beta and spot me online!