I got the beta on thursday and I thought I'd talk about a few things involved with th game.
1. No Auto-aim
Bungie seems to have removed auto-aim almost altogether making sniping and aiming a different experience.
2. Assasinations
If you weren't aware, assasinations now come with shiny new animations when you hold down the melee button instead of simply pressing it. It doesn't give you anything extra or serve any purpose other than giving you a good lol. But while mid-animation, someone can kill you and save their teammate.
3. Matchmaking
Not all gametypes will be avaliable from download. When the beta opens up, the playlists will be
a.) Grab Bag - A mix of objective gametypes and slayer
b.) FFA - A free for all playlist featuring objective and slayer gametypes
c.) Arena - The only ranked playlist, slayer gametypes.
Invasion and generator defense will not be open until May 7th for invasion and May 14th for Generator Defense.
4. Credits and ranking up
You ern credits each game based on how well you do and how many medals you earn. They are spent by buying armor permutations such as shoulders and chests pieces or helmet attatchments. Experience which I believe is relative to the number of credits you earn, decides when you rank up.
5. Customization
There are about 4 helmets you can purchase, 4 chests, 4 shoulders of each kind, and 3-4 add-ons for each helmet. Your service tag can be up to 4 characters of letters, numbers, and some speial characters. There are a few new emblems and some new colors to use on your armor andemblem as well.
Hope this helped even though the beta releases tomorrow...