I played Halo 5 for about 4 hours last night. I started out by running my campaign on Legendary and damn, this game is hard. The smaller battles are easy but when they start packing on the enemies, it gets so difficult. The Promethiens in particular are very difficult because the crawlers are good at flanking you and because the Boltshot now tracks you, they can hit you even when you cannot see them.
I really like what 343 did with the Jackels. It's cool to see variants that use automatic weapons and their agility makes them a really interesting enemy. I also like that the Hunters have been turned up to 11. I remember playing through Halo 1 and seeing them in the Silent Cartographer for the first time and they literally scared me. Then I found out that you could circle around them and take them down with a single round and that ended that. The H5 Hunters can really take a punch. On one of my many tries at a certain battle in Mission 2, it took me about 5 rounds from the Railgun and 3 rockets to kill one of them. It's good that the tried and true, "hit them in the back" strategy still works though because in another try, I took one down with 4 Railgun rounds.
The Promethiens are also more interesting to fight. Soldiers add something to the battle field that Knights didn't. I like how they teleport around the battlefield but that you can see where they went. The Halo 4 method of teleportation made Knights that teleported a pain in the ass. Speaking of Knights, these ones are awesome. I like the addition of the weak points and it's a lot of fun to see their armor break before you land the killing blow.
I was only able to finish 2 levels in two and a half hours before moving on to Multiplayer. I played three games of Warzone and one CTF game in Arena. On the first two games of Warzone, I was on a team that dominated. On the third, we had a really close battle that came down to the other team getting the final shot on the Warden. That kill put them up by about 30 and we were never able to recover. We ended up losing 1000 to about 980ish. That game showed me the potential of the mode.
I had to tend to my baby eventually but I was able to get one game of CTF in on Truth. Let's just say that I cannot wait to play more.