I feel like Halo could learn a lot from the new Doom games in order to revitalize its combat and keep things fresh. In fact, the brief gameplay segment we got of Halo Infinite did seem to me that it was incorporating a bit more of Doom 2016's push-forward approach and physicality, though that could just be down to the player consciously being aggressive.

Halo was great when bungie was producing it’s now an underachiever so I’d say doom currently and halo from 1-reach

I loved the the first three doom games. The third felt a bit like a survival horror with an amazing atmosphere. Can't stand the new Doom games. Now execute someone...Now chainsaw someone...For ammo or health annoys me. I miss Doom I-II/Duke Nukem 3D games. The FPS/Puzzle/Secrets is real fun for me.

Have to say the two are completely different.

IMO, truer rivals would be Doom v Half Life or Halo v COD.

FPS have never been my cup of my tea, but I have enjoyed playing Halo. I could never get a hold of Doom. I remember many years ago my older brother used to play it a lot, and then I tried and didn't like it. I've tried a couple of time in later years, but nope.

Doom. I've honestly played the majority of DOOM games, while I've only played Halo 1,2 and 4, and the way Halo's story has been warped from Bungie to 343, I wasn't really interested all that much in Halo anymore, but DOOM still keeps me very much interested.

I don't see it as a rivalry, they are the same genre but play very differently.

Halo has a much bigger emphasis on story and narrative, Doom is 100% balls to the wall action nonstop.

I haven't played Halo 5, and from what I've seen I must say it does seem like a misfire, but I don't get the hate for Halo 4, I thought 343i did a good job on that one.

The reason these two Juggernaut series clash isn't for the way they play. You are correct in that they are different, however so was Mario to Sonic to Crash, very different platformers but they fought for the same title. The rivalry isn't based on simply gameplay comparisons, but more on history and ideas. Both Doom and Halo series rely on a Green Super Solder from the future, both fight unbelievable odds, both are super badass characters and both have been considered the FPS kings at one stage or another. Doom was the Hulk Hogan of FPS where as Halo is like the Rock. They too are also very different wrestlers but same conversation as who's the best wrestler of all time.

Correct the games aren't the same but they offer a lot of resemblance to each other and compete for the same talking points. Doom was the original badass Green Super Solder, lost his title to the new kid on the block with the Master Chief and only recently reclaimed his crown.

Also remember the creators of Halo were trying to make a Doom successor/knockoff from the very beginning (Marathon) back when Half Life and COD weren't even a sketch on paper. Bungie eventually succeeded by creating their very own Green Super Solder. Its just a very fun comparison to make. When you think of FPS games, its hard to think past Halo and Doom. 

I feel like part of the seesaw between the two was that Doom arrived during a time when gaming was about straightforward arcadey action, then later Halo's open levels, vehicles, etc added a whole new level of complexity to games that was novel and mindblowing at the time. This ushered in a new era and Doom felt antiquated for the moment.

Then, many years later at a time when basically everything was going with big open worlds all that, Doom 2016 came along and succeeded by appealing to that same old elegant arcadey simplicity that had been all but lost from big budget gaming at the time.