What’s the best way to make interesting bosses, or enemy encounters where you fight more than one boss, or enemy at the same time?
Well, I’m not gonna say this is the best, but some things to consider are the ways different enemies divide up space. Like in Nier Automata, some enemies have lasers that cut across a part of the battlefield, some shoot huge clusters of bullets that need to be shot through or moved around, some get up close and flail their arms to keep out a constant hitbox, making them actually exploitable to get perfect dodges.
The key thing is making sure the enemies overlap in different ways. The most common example of this ever is a ranged enemy plus a melee enemy, or a rushdown enemy plus a slower enemy with wide hitboxes.
It’s also possible to combine enemies of the same type effectively, if they can play different roles based on positioning. DMC1 gives all enemies both close range and far ranging attacks since it’s limited to 1 enemy per room. The other thing is considering how well the enemies work when they’re spread out, versus how well they work when they’re close together, and how they all move relative to each other. Do they tend to bunch up? Can they move in formation? Do they circle around the player, or do they keep their formation loose so if the player moves away or around them, they’re still potentially in danger? Do they block off the way forward, do they block off your retreating path? Think about how they can take advantage of their positioning relative to the player, each other, and the environment.
As for Group AI, some games like Assassin’s Creed and Batman have coordinating group AI that makes all the enemies surround you and attack one at a time. If you’re going to do this, don’t both including multiple enemies, just include one with 6 times as much health. The point of having multiple enemies is so they can attack with asynchronicity. They cover different options at different times over different periods. Because you have these enemies that move independently of one another, independently they might not be a threat, it might be simple to counter their actions if they’re alone, but together their actions combine and overlap on top of one another, so you need to watch what’s going on, and think about the situation you’re currently in. You’re gonna learn how all the enemies attack, so then you can see them attacking and put it together in your head, “Oh, if this guy attacks at this time in this spot, and this other one attacks at this time in this spot, then my best option for this situation is gonna be this”. Group AI still makes sense, it’s how enemies can coordinate for higher level tactics, like special combination attacks, or staying in formation. Group AI is also helpful for preventing the AI from checkmating the player. It’s entirely possible that the AI might attack in ways that have no solution, and ideally a coordinating group AI would help prevent these corner cases without totally invalidating the fact that you have multiple enemies.
The last Dark Souls 3 DLC had a great multiple enemy encounter with The Demon in Pain that’s probably worth referencing. The two demons in that fight would periodically switch roles between aggression and ranged support. And the primary ranged attack was like a really long range shockwave that was first signaled with a cloud of smoke, so even if your camera was pointed away, you could still tell bad shit was going to go down on the spot where you were standing.
Also give the player a pillar to circle strafe maybe.