With Halo: Reach being Bungie's swan song for the series, it seemed the right time for a group of Halo experts to figure out which Halo game is the hardest. Among the committee that spent dozens of hours debating (and by hours, I mean minutes) are Halo aficionados Hilary Goldstein (that's me!), Will Tuttle, David Clayman, Erik Brudvig, Arthur Gies, and Nate Ahearn.
We judged the overall campaign difficulty for each game, considering both the single-player experience and the co-op experience. And always with a mind on the Legendary difficulty, since that's the true measure of each Halo experience. Co-op difficulty was a major influencing factor in the overall rankings, since many of the single-player experiences are fairly comparable for most of the games in the series.
Here are our picks from easiest to hardest.
Halo: Combat Evolved
Scared Little Grunt
It might have seemed tough nine years ago, but give Halo: CE a try now and you'll likely find yourself giggling at how easy it is to take down the Covenant. Despite the lack of cool moves like vehicle jacking, the weapons hold a ton of ammo, you can stock up on grenades, and the assault rifle is a beast. All the years of playing Halo make the original a cake walk. Which isn't necessarily a bad thing. The series should continually get tougher.
Halo 3
Non-Sniping Jackal
Even Bungie admits that Master Chief had turned into a super hero by Halo 3. Though the single-player may be comparable in difficulty to some of the other games (Flood snipers, really?!), the challenge is negated the minute your friends join in. Halo 3's co-op campaign doesn't scale. That means the challenge is three times less when you have three friends playing with you. Not an exaggeration: We beat Halo 3 on Legendary with four players in just a couple of hours at the review event.
Halo 3: ODST
Angry Brute
Putting you in the shoes of an ODST meant your character's abilities had to be stifled. No more super-human Master Chief stuff. You get one weapon to wield and, in the spirit of the first Halo, you have health that doesn't automatically regenerate but requires health packs. ODST is actually toughest at the outset, because it's hard to accept that, as a lone wolf ODST, you just shouldn't try and stand toe-to-toe with every enemy you encounter. It takes some time to acclimate, and once you do, caution is often the smarter choice over the usual Halo bravado.
Halo 2
Sword-Wielding Elite
Those God damned Jackal snipers, am I right? Anyone who played Halo 2 on Legendary can attest to how incredibly annoying those snipers could be. They could snipe the pixel off a gnat. But where Halo 2 gets really tough is when you play co-op. When one person dies, you're both sent back to the last checkpoint. When you have some truly tough (and unfairly accurate enemies) this can make progression through the campaign with a buddy close to impossible at times.
Halo: Reach
Many, Many Hunters
Bungie promised that Halo: Reach was the hardest Halo game and that was no lie, due to scaling cooperative play. The campaign has some tough difficulty spikes towards the end, but nothing a seasoned vet can't fight their way through. It's hard, don't get me wrong, but it's not impossible on your own. However, the difficulty scales in co-op, meaning that if you have three friends in tow, the game is basically three times as hard. Considering that Halo: Reach is already a pretty hard game to beat, upping the difficulty provides, well, a legendary challenge that only the best group of Halo players can hope to overcome.
Link -- http://xbox360.ign.com/articles/112/1121324p1.html
I pretty much agree with IGN's list except I would switch Halo Reach with Halo 2...that game was disgustingly hard.
Essay Pro