Okay, so, I've played Doom Eternal for about 1.5 hours. I said I'd give my thoughts, so here they are.
Doom Eternal is, overall, better than Doom 2016, but that isn't to say that it's "good." At least, not for me. It's to Doom 2016 what Doom II was to Doom I - more of the same, but with additions. If you loved Doom 2016, you'll love this. If you liked Doom 2016, you'll like this. If you disliked Doom 2016, you'll dislike this. From what I've played so far, Doom Eternal isn't going to shift your perspective on the rebooted series much.
Like I said though, Doom Eternal is still an improvement over its predecessor. On the gameplay front, we've gone from the hell portal mechanic. Y'know how you basically had to activate a fight via the pulsating things, and the things would die or be destroyed when you killed all the demons? Yeah, that's gone. You're still locked into arenas at times (there's these Hell gate things that won't deactivate until enough demons have been killed), but there's less of a sense of artificiality. In D2016, you activated an arena fight. In DE, you kind of stumble into an arena fight, if it's an arena fight at all. It's a small difference, but it's one I appreciate.
Something I also appreciate (well, sort of), is that there's more strategy involved. Some demons are specifically vulnerable to specific weapons. For instance, the Arachnatrons and Cacodemons are both vulnerable to your shotgun's grenade launcher, the later especially. Your flamethrower will cause enemies to drop armour, which introduces a sort of loot system - longer they're on fire, the more armour they drop, but the longer they're on fire, the longer they have to kill you. It's a sort of mini risk/reward system. Also the dash is fun to use, and the platforming is...decent. Honestly, it's kind of quaint for platforming to be in an FPS these days, but here we are. That said, less than 2 hours, and I'm already kind of bored. You find demons, you fight demons, you kill demons, you move to the next area, you kill some more demons. I know that's what Doom IS, but I'm already getting tired of it. Point is, the gameplay of DE is improved from D 2016, but it's not enough to make me love it.
On the flip side, there's the story/lore. One of my complaints about Doom 2016 is that its story and lore felt haphazard, like someone was just throwing it together on the fly, but left me wanting more (e.g. Argent D'Nur). Doom Eternal has the opposite problem. As in, the lore feels better put together (note that when I say lore, I mean codex entries), but the flipside is that I find myself unable to care about, well, anything. Oh sure, it's explained how Earth's forces are holding out, and their plan to escape the planet (hello Doom 2), but you never see another living human. Oh sure, it's nice to visit Argent D'Nur (wasn't it consumed by Hell though?), but it's really just Caliban from Warhammer 40,000 (also there's Imperial Titan wreckages on Earth, or what look like them). Oh sure, it's nice to learn a bit more about Hell, but I just find myself unable to care about anything that's going on, especially when in the first two hours, I'm expected to learn about the ARC/Allied Nations, Hell, the Night Sentinels/Argenta, and there's already references to Heaven (I may have seen an angel, but I'm not sure what IT is).
I think a part of the problem here is that clearly the Doom Slayer knows much more about what's going on than me, and codex entries aren't enough (and it's not like I'm missing them). How is VEGA with him? Where did the Fortress of Doom come from? What's his relationship with King Novik? I mean, some of these questions will presumably be answered, but the protagonist knows stuff ahead of me, and honestly, it's jarring at this point. The protagonist knowing more than the reader/watcher/player isn't new, but here, it's particuarly egregious, at least for me. So, at the end of the day, so far, Doom Eternal has better crafted lore than Doom 2016, but I find myself caring less about it. If you paid any attention to the lore in Doom 2016, I don't know how you'll react to this. Honestly though, if you didn't care at all about the lore/story, you might find yourself resenting this because there's third person cutscenes in the game that do go on at times (though I'm pretty sure you can skip them). Doom Eternal is certainly more vested in telling a story, I just don't think it's a particuarly engrossing one.
So, TL, DR, Doom Eternal is overall better than its predecessor, but it's still not a game I'm enamored with. As heretical as it sounds, Doom 3 is still my favourite in the series.
Doom Eternal is, overall, better than Doom 2016, but that isn't to say that it's "good." At least, not for me. It's to Doom 2016 what Doom II was to Doom I - more of the same, but with additions. If you loved Doom 2016, you'll love this. If you liked Doom 2016, you'll like this. If you disliked Doom 2016, you'll dislike this. From what I've played so far, Doom Eternal isn't going to shift your perspective on the rebooted series much.
Like I said though, Doom Eternal is still an improvement over its predecessor. On the gameplay front, we've gone from the hell portal mechanic. Y'know how you basically had to activate a fight via the pulsating things, and the things would die or be destroyed when you killed all the demons? Yeah, that's gone. You're still locked into arenas at times (there's these Hell gate things that won't deactivate until enough demons have been killed), but there's less of a sense of artificiality. In D2016, you activated an arena fight. In DE, you kind of stumble into an arena fight, if it's an arena fight at all. It's a small difference, but it's one I appreciate.
Something I also appreciate (well, sort of), is that there's more strategy involved. Some demons are specifically vulnerable to specific weapons. For instance, the Arachnatrons and Cacodemons are both vulnerable to your shotgun's grenade launcher, the later especially. Your flamethrower will cause enemies to drop armour, which introduces a sort of loot system - longer they're on fire, the more armour they drop, but the longer they're on fire, the longer they have to kill you. It's a sort of mini risk/reward system. Also the dash is fun to use, and the platforming is...decent. Honestly, it's kind of quaint for platforming to be in an FPS these days, but here we are. That said, less than 2 hours, and I'm already kind of bored. You find demons, you fight demons, you kill demons, you move to the next area, you kill some more demons. I know that's what Doom IS, but I'm already getting tired of it. Point is, the gameplay of DE is improved from D 2016, but it's not enough to make me love it.
On the flip side, there's the story/lore. One of my complaints about Doom 2016 is that its story and lore felt haphazard, like someone was just throwing it together on the fly, but left me wanting more (e.g. Argent D'Nur). Doom Eternal has the opposite problem. As in, the lore feels better put together (note that when I say lore, I mean codex entries), but the flipside is that I find myself unable to care about, well, anything. Oh sure, it's explained how Earth's forces are holding out, and their plan to escape the planet (hello Doom 2), but you never see another living human. Oh sure, it's nice to visit Argent D'Nur (wasn't it consumed by Hell though?), but it's really just Caliban from Warhammer 40,000 (also there's Imperial Titan wreckages on Earth, or what look like them). Oh sure, it's nice to learn a bit more about Hell, but I just find myself unable to care about anything that's going on, especially when in the first two hours, I'm expected to learn about the ARC/Allied Nations, Hell, the Night Sentinels/Argenta, and there's already references to Heaven (I may have seen an angel, but I'm not sure what IT is).
I think a part of the problem here is that clearly the Doom Slayer knows much more about what's going on than me, and codex entries aren't enough (and it's not like I'm missing them). How is VEGA with him? Where did the Fortress of Doom come from? What's his relationship with King Novik? I mean, some of these questions will presumably be answered, but the protagonist knows stuff ahead of me, and honestly, it's jarring at this point. The protagonist knowing more than the reader/watcher/player isn't new, but here, it's particuarly egregious, at least for me. So, at the end of the day, so far, Doom Eternal has better crafted lore than Doom 2016, but I find myself caring less about it. If you paid any attention to the lore in Doom 2016, I don't know how you'll react to this. Honestly though, if you didn't care at all about the lore/story, you might find yourself resenting this because there's third person cutscenes in the game that do go on at times (though I'm pretty sure you can skip them). Doom Eternal is certainly more vested in telling a story, I just don't think it's a particuarly engrossing one.
So, TL, DR, Doom Eternal is overall better than its predecessor, but it's still not a game I'm enamored with. As heretical as it sounds, Doom 3 is still my favourite in the series.