(Replayed on MCC on PC with gamepad, Legendary, skipped The Library)
Honestly a lot better than I remember. I think the common praise and complaints about this game are mostly correct in kind if not always magnitude, so let me discuss some interesting specifics.
The Library is awful and you should skip it if possible. The campaign's pacing is significantly improved without it, it emphasizes everything bad about the game while downplaying everything good, Bungie devs have stated multiple times that it shouldn't have been shipped, etc. Everyone knows it's trash and I'm going to pretend like it doesn't exist now, moving on.
Weapon balancing here is my favorite in the series. Everything feels powerful and situationally useful. The pistol, shotgun, and power weapons are obviously good, but the plasma pistol has great accuracy and damage even with the primary fire, the plasma rifle stuns enemies who take sustained hits, and the needler is a great Elite killer if you have the positioning for it. Even the assault rifle occasionally comes in handy against Grunts or Flood.
A huge issue with this game is the difficulty balancing. Heroic is hilariously easy for some reason, with even high-rank Elites quickly melting to plasma pistol fire. Legendary has a lot of nice changes to health (Elites don't die instantly), enemy encounters (more enemies with higher ranks), and AI (dodges grenades and fire more often), but you also take tons of damage, especially on your shield. This makes it easy to get stuck on one health pip for long periods, which makes the game into more of a cover shooter, encourages the linear playstyles like plasma pistol overcharge sniping, etc. This could have been fixed by simply placing more health packs (occasionally this does happen, why does Keyes have so many?) or perhaps raising the minimum health value like Reach did. All that being said, if you are good at single-player FPS I would still recommend Legendary, or maybe Heroic with some specific skull combination.
Enemy design and AI (of the Covenant) is stellar. This is well-known and discussed, see here and here for some other people's writeups.
Flood, not so much. A melee-focused swarming faction is an okay idea on paper, but they don't have anything close to the Covenant's differentiation, AI behaviors, or health/shield tradeoff. Fighting them isn't horrible, but I'd be lying if I said I ever looked forward to it. Special dishonorable mention to the infection forms, which block checkpoints and are constantly a chore to clean up. Thankfully, many of your encounters with the Flood are in infighting scenarios where they can be toyed with or ignored.
The level design isn't as bad as most suggest IMO. It's less that they reuse environments, and more that a bunch of the missions are too long. Assault on the Control Room has you fight in the same room + bridge geometry 3 times, but they try to mix it up with different enemy compositions (especially notable: the bridge with Elites blocking your path while Hunters on the other bridge shell you across the gap). But there aren't enough unique ideas to totally sustain the momentum, and I suspect they would have had difficulty adding more.
Let me elaborate. There are broadly two styles of FPS enemy design. On one end is Doom, whose enemies are simple but highly differentiated, and form interesting situations with how they are placed and combined by the mapper. On the other is Half-Life and FEAR, whose enemies are complex but similar, and present new situations via the dynamism of their AI. Halo is great because its AI belongs to the latter school, but its enemy designs bring in much of the former's differentiation.
A side effect of this though is that the levels in general don't feel as distinct from each other as e.g. Doom maps might, since the enemies and weapon economy are less sensitive to small tweaks in placements and terrain. Halo 3 gets around this by using tons of setpieces, though this has the tradeoff of needing more budget and potentially feeling gimmickier (and 3 has the unforced error of worse fundamentals than 1). Perhaps they could have made more arena geometries, but I suspect the lowest hanging fruit was all picked, so the game should have just been a bit shorter.
After this playthrough, I'm comfortable calling Halo my favorite of the "dynamic AI driven FPS", (with classic Doom the king of the opposing style) and Halo 1 tied with 3 for my favorite entry in the series. Great stuff!
Honestly a lot better than I remember. I think the common praise and complaints about this game are mostly correct in kind if not always magnitude, so let me discuss some interesting specifics.
The Library is awful and you should skip it if possible. The campaign's pacing is significantly improved without it, it emphasizes everything bad about the game while downplaying everything good, Bungie devs have stated multiple times that it shouldn't have been shipped, etc. Everyone knows it's trash and I'm going to pretend like it doesn't exist now, moving on.
Weapon balancing here is my favorite in the series. Everything feels powerful and situationally useful. The pistol, shotgun, and power weapons are obviously good, but the plasma pistol has great accuracy and damage even with the primary fire, the plasma rifle stuns enemies who take sustained hits, and the needler is a great Elite killer if you have the positioning for it. Even the assault rifle occasionally comes in handy against Grunts or Flood.
A huge issue with this game is the difficulty balancing. Heroic is hilariously easy for some reason, with even high-rank Elites quickly melting to plasma pistol fire. Legendary has a lot of nice changes to health (Elites don't die instantly), enemy encounters (more enemies with higher ranks), and AI (dodges grenades and fire more often), but you also take tons of damage, especially on your shield. This makes it easy to get stuck on one health pip for long periods, which makes the game into more of a cover shooter, encourages the linear playstyles like plasma pistol overcharge sniping, etc. This could have been fixed by simply placing more health packs (occasionally this does happen, why does Keyes have so many?) or perhaps raising the minimum health value like Reach did. All that being said, if you are good at single-player FPS I would still recommend Legendary, or maybe Heroic with some specific skull combination.
Enemy design and AI (of the Covenant) is stellar. This is well-known and discussed, see here and here for some other people's writeups.
Flood, not so much. A melee-focused swarming faction is an okay idea on paper, but they don't have anything close to the Covenant's differentiation, AI behaviors, or health/shield tradeoff. Fighting them isn't horrible, but I'd be lying if I said I ever looked forward to it. Special dishonorable mention to the infection forms, which block checkpoints and are constantly a chore to clean up. Thankfully, many of your encounters with the Flood are in infighting scenarios where they can be toyed with or ignored.
The level design isn't as bad as most suggest IMO. It's less that they reuse environments, and more that a bunch of the missions are too long. Assault on the Control Room has you fight in the same room + bridge geometry 3 times, but they try to mix it up with different enemy compositions (especially notable: the bridge with Elites blocking your path while Hunters on the other bridge shell you across the gap). But there aren't enough unique ideas to totally sustain the momentum, and I suspect they would have had difficulty adding more.
Let me elaborate. There are broadly two styles of FPS enemy design. On one end is Doom, whose enemies are simple but highly differentiated, and form interesting situations with how they are placed and combined by the mapper. On the other is Half-Life and FEAR, whose enemies are complex but similar, and present new situations via the dynamism of their AI. Halo is great because its AI belongs to the latter school, but its enemy designs bring in much of the former's differentiation.
A side effect of this though is that the levels in general don't feel as distinct from each other as e.g. Doom maps might, since the enemies and weapon economy are less sensitive to small tweaks in placements and terrain. Halo 3 gets around this by using tons of setpieces, though this has the tradeoff of needing more budget and potentially feeling gimmickier (and 3 has the unforced error of worse fundamentals than 1). Perhaps they could have made more arena geometries, but I suspect the lowest hanging fruit was all picked, so the game should have just been a bit shorter.
After this playthrough, I'm comfortable calling Halo my favorite of the "dynamic AI driven FPS", (with classic Doom the king of the opposing style) and Halo 1 tied with 3 for my favorite entry in the series. Great stuff!