Most people that know me know that I don't regard the Halo series as highly as most. Maybe it was because I had access to gaming PCs since 1997 so didn't see the big deal about Halo. Some people saw some huge leap in the FPS genre. I just was a really well made FPS game that had some flaws (reuse of assets and the Flood being so lame). I can be a bit critical of the games but I do enjoy them, just some people think I hate them and attack me for it. Well, maybe the single player portion of Halo 2 was rubbish but other than that I do think they are good games.
Halo 3: ODST however I really don't like. After reading about how much it changed the basic Halo formula and the good reviews I picked up a copy cheap and played while I was taking a much needed break from Dark Souls. I wasn't expecting to be blown away but I also wasn't expecting it to be so bland. The open world sections of the game are a good change of pace but I don't think the game really pulls them off that well. It's not very often that you meet a covenant patrol and they are so small that they don't put up much of a fight. It's a bit of a wasted oppurtunity. The game goes back to traditional Halo during many of the flashback sequences and while these are fun, it's really more of the same Halo gameplay. The game finally takes a nose dive in quality during the final stretch when the plot gets so ridiculous and stupid that I can't believe nobody at Bungie complained before ending on a whimper. The dialogue throughout the game is also badly written and laughabl in some places. The only part of the game that didn't disappoint was the surprisingly good soundtrack.
I also got Halo Reach at the time and wwas prepared to be disappointed again but so far it actually seems like a really solid game. So far it all takes place it large open environments were the series excels and forgoes the linear tight corridors made of repeated art assets. It seems to be the Halo game that the series has been trying to be for the last 10 years.