After beating Halo 2, I had tried to find some words to write about it. After all, it's this huge landmark game that helped define multiplayer shooting for an era, and it attempted to tell a large space opera-ass story spanning multiple games. What I've come away with though is nothing to do with plot, or setting, but encounter design. Halo 2 does what I love about Id-made Doom games: They utilize their fodder enemies excellently.
This dovetails nicely with some thoughts I'd been having lately about why I don't like the Plutonia Experiment wad for Doom, but I love playing Doom 2. Halo was just the needed step to make me realize it. What some games, and some wad makers for Doom do is they just keep escalating and escalating. Halo 2 does this to a point, where all you're doing is fighting tough Brutes, but then you'll get a sprinkling of Jackals, or weaker Flood enemies mixed in. Or it'll pull things back enough where you're facing a few Elites and some Grunts.
You can see why a game would just keep escalating. You're nearing the end, you need to be challenged, you need bigger, tougher enemies to indicate this. You don't need the weak enemies anymore, because you're past them, right? Nah. Your fodder enemies should be used throughout the game. Early on, they serve as a way for you to get your bearing in the game, and later on, they can provide a sense of overwhelming enemy number, they can provide a change of pace from an intense encounter, and they can let you feel like an absolute monster by allowing you to tear through them. If your game doesn't have a power progression, they can also provide just as much of an issue at the last level as they did the first.
The last point is a strong point in Halo's favor. You're not really getting stronger as you play the game, so the enemies are just as threatening, but later on in the game, you know how they fight. You know the best way to engage them, so even though your tools haven't changed much, you will can face them more and more efficiently. This is similar, but not quite the same in Doom. Imps are still a threat in Doom. Their fireballs do the same damage in the first stage as the last, but your ability to deal with them increases as you progress through the game. Doom makes some fascinating decisions with this, as your arsenal expands. For some encounters, it'll be just as straightforward as early levels "Here are 3 imps in this hallway, rip and tear". Others, they'll put them behind a wall and have them try to ambush you. Other times still they'll try to overwhelm you with numbers. Others still they'll sprinkle in a harder enemy with these fodder enemies, so you have to try to fight through the wave to get to the priority target.
You can still have your boss encounters, of course. A level after Gravemind in Halo 2 that's a big ol battle arena room fits that bill, as does the rooms where you're circle strafing the Cyberdemon while dodging Imp fireballs. These act like your large spikes in intensity, while the grunt type enemies can be used to give you a relaxation period between these moments of high intensity and chaos. If all you're doing is escalating, it gets hard to catch your breath, and one thing that may be a cool encounter or setpiece gets overwhelmed by the next piece of explosive action. For intense moments to hit, you do need to give them a few moments to breath and linger. You need those rooms with either no enemies or weak enemies to help you come down off that elevated state.
These varied encounter designs keeps a game engaging and prevents it from suffering from Escalation Fatigue. You can see Escalation Fatigue in some RPGs where enemies who were bosses become standard enemies, because the game needs to show how strong you've gotten. Good use of a game's entire enemy bestiary helps reinforce your games character and enemy design and lets you make more enjoyable encounters because it allows players to gain familiarity with what they're facing. I love the way Halo handles this for the most part, and I was wondering why it kept giving me Doom vibes, and I think this is it. Interesting encounter design drive my interest in Doom, and Halo scratches that same itch.
