The metrics of video game difficulty change from genre to genre. Usually, the best way to judge a challenge is by quantifying the amount of punishment enemies can take. Or to put it in gaming terms, whether enemies are “bullet sponges.” Quite frankly, way too many games depend on that trope.
It’s important to quantify what a bullet sponge actually is. As the basic term implies, it is an enemy that soaks up bullets like a sponge soaks up water. If a game doesn’t actually feature bullets, the term “damage sponge” could easily be applied instead.
While many games feature enemies that take multiple hits to beat, that term doesn’t necessarily apply to all of them. It’s usually reserved for a certain type of enemy that takes way too long to die but doesn’t provide a satisfying challenge in return. Other times, bullet sponges are simply enemies that are basically massive target dummies designed to encourage players to obtain better gear and provide an artificial sense of difficulty. Bosses can certainly be bullet sponges, but more and more games are turning basic enemies into bullet sponges as well. Many games don’t even bother to explain why those basic enemies are capable of taking so much damage. If an enemy takes way too long to kill without earning that challenge (or provides the wrong kind of challenge), it’s likely a bullet sponge.
Some of the most recent (and egregious) bullet sponge enemies come from online looter shooters such as Destiny/Destiny 2 and The Division/The Division 2. Both franchises feature bullet sponges in their purest form: enemies that take an unrealistically long time to kill and offer little in the way of actual challenge, thus dragging their fights into dull monotony. In Destiny, most bullet sponges are bosses and other foes significant to the storyline. In games like The Division, though, virtually every enemy is a bullet sponge. You can pour entire clips into them, and they won’t die until you’ve whittled away the surprisingly generous health bars nearly every member of the opposition is blessed with.
The rise of bullet sponge design in such games is likely an unfortunate side effect of trying to combine FPS and MMORPG design tropes. Damage in many MMORPGs is often determined by a combination of gear, character levels, and abilities. The better a player’s equipment, build, and abilities, the more damage they tend to do. It’s a natural progression mechanic that emphasizes the role-playing part of the MMORPG.
Like many MMORPGs, though, your gear in Destiny and The Division is often dictated by RNG. If luck isn’t on a player’s side, they won’t get the guns or armor that let them keep up with enemies. Moreover, better player equipment doesn’t fix a lack of enemy abilities. Fights soon devolve into managing ammo so that you can win eventually. What’s often missing is a substitute for the way that such fights in MMORPGs are often actually a test of your understanding of your character as well as your gear, builds, and skills. You’re still required to play Destiny and The Division like shooters, but fundamental shooter concepts (like aiming) are a masquerade for the calculations happening in the background. Some RPG concepts just dont’ translate well to shooters.
It’s not just online games, though. Plenty of single-player games (or games with optional multiplayer) also sport annoying bullet-spongey enemies. Case in point, Warden Eternal in Halo 5. Arguably the most aggravating enemy in the game, if not the franchise, Warden Eternal serves as one of Halo 5’s bosses. He doesn’t do anything special, though. Players just have to pepper him with bullets until he finally keels over. But then he returns as another boss fight. And then another. Not exactly creative, especially when you consider that the Halo franchise was built to evolve combat through advanced enemy A.I. that demanded advanced player tactics (at least until The Flood came along).
Worse are the times when bullet sponges are used to artificially inflate difficulty. In Uncharted 2, for instance, players eventually face off against Shambala Guardians that can withstand an entire magazine to the face without dying and have access to ranged and incendiary weapons. The Gears franchise is filled with difficulty spike bullet sponges, such as the Berserkers, and enemies that can withstand incredible amounts of damage for no good reason (looking at you Gears of War 4‘s robots). Even the Mass Effect series turns enemies into bullet sponges to service its optional harder difficulty modes.
Given all these examples, it’s easy to assume any enemy or boss that sports a gargantuan health bar is a poorly-designed damage sponge. However, the game industry is full of exceptions. Bullet sponges (and enemies featuring bullet sponge features) dont’ have to be a bad thing.
The secret sauce is a combination of moment-to-moment gameplay and tangible rewards. The Borderlands games are filled with bullet sponge enemies, but those games embrace that concept by following dungeon-crawler, loot-based logic. Weaker enemies only provide maybe one or two weak rewards at best, but these items can be cashed in to help players afford better store-bought weapons. Bosses, meanwhile, tend to drop potentially powerful items that are good for quite a few levels. They’re not for everyone, but those games embrace looting and the idea that enemies are a test of your loot in ways that make their bullet sponge design a bit more reasonable. Unlike some online looter shooters, they also don’t use that design to push microtransactions (except for DLC expansions).
Enemies with hilariously large health bars also aren’t inherently a bad thing. Yiazmat from Final Fantasy XII might take hours to defeat, but it provides one of the badges needed to acquire the game’s strongest weapon. Resident Evil 3‘s Nemesis is a pursuer enemy that can absorb an absurd amount of damage, but anyone with enough patience and ammo can temporarily down the Nemesis and acquire parts to build an overpowered pistol and shotgun. These bosses demonstrate some of the ways you can properly design enemies with bullet sponge-level health.
Soulsbornes and franchises such as Touhou Project and Monster Hunter even use seemingly overpowered enemies to effectively increase their difficulty. What prevents these bosses from falling into the bullet sponge trap? Their presentation helps (battles against such enemies should feel epic and not routine), but the most important ingredient is a challenge delivered via pattern recognition and memorization. Each enemy looks intimidating if not downright impossible at first, but the more times a player fight them, the more they mentally break down a boss’ attacks. Eventually, players memorize these patterns and know not only how and when to dodge but also how and when to counterattack. Sure, these bosses take almost forever to defeat (Monster Hunter quests often give players a 50-minute time limit since 20-30 minutes are spent wailing on the monsters), but challenge and spectacle justify their durability. Victory in those games feels earned.
Implementation aside, the big problem with bullet sponge design is that it has become so common. Some games just don’t use bullet sponge mechanics well, but some don’t need bullet sponges at all. Games like the Max Payne franchise and Dead Space show how to do fun shooting mechanics that focus on precision aiming and movement. The Ratchet and Clank series show how big guns can be big fun even if enemies don’t always scale to resist their damage. Even the Far Cry franchise used to feature intense tactical combat before that franchise embraced bullet sponge design. There are several viable alternatives to bullet sponge design, and there have been for a while. We just seem to be firmly stuck in an era of bullet sponge design in Triple-A action games, and it’s costing us worthwhile experiences that used to be easier to find.
The bullet sponge concept isn’t going anywhere, and that’s not necessarily a bad thing. It’s just that bullet sponge developers need to ask more questions before they settle on that approach. Is the fight engaging and/or challenging? Is there a lore or narrative reason why this enemy can withstand so much damage? Is the fight optional? Does it offer rewards that feel proportional to the time that went into the encounter? If those criteria are met, then you might have a bullet sponge that can absorb the player as easily as it absorbs damage. But if an enemy has so much health and attacks no more devastating than the damage done to your trigger finger…well, maybe it’s time to realize that not everything has to be a bullet sponge.