Mechanics: Damage Over Time

            Lately I've been playing Darkest Dungeon by Red Hook Studios, and it’s made me think about the popularity of damage over time effects in games. Geoffrey Zatkin coined the acronym DOT during Everquest development. I did a quick internet search, and did not find any specific information on the earliest appearance of ongoing damage effects, but my money is on an early edition of Dungeons & Dragons.

            It’s not surprising that damage over time would show up soon after then invention of “hit points.” DOT is extremely flavorful. It does a great job of conveying popular game concepts like poison, acid, and other maladies that take their sweet time in killing your character. But damage over time isn’t just an ornamental mechanic; if used thoughtfully, ongoing damage effects can contribute a great deal to a game’s strategic depth, and can be used to solve tricky design challenges.

Darkest Dungeon - The Plague Doctor class both causes and cures ongoing damage effects.

Darkest Dungeon - The Plague Doctor class both causes and cures ongoing damage effects.

            The core strategic functionality of damage over time derives from the fact that it is inherently a drawback. Delaying damage gives the target more time to attack you, heal themself, or use an ability to negate the ongoing damage effect. To compensate for this, attacks that deal their damage over time can be strengthened in other areas, namely their total damage. The most potent examples are effects that inflict damage indefinitely, like the poison condition seen in the Pokemon franchise. If the effect is indefinite, it will eventually eclipse all attacks that deal a finite sum of damage. Even effects with a limited duration should, if carried to completion, outstrip their immediate-damage counterparts.

            Essentially, DOT attacks ask players to look ahead and determine if they will get the full value of the attack before the target falls. Because of mechanics like damage over time, Darkest Dungeon's turn-based combat system feels like a puzzle. Each turn is an attempt to distribute my party's damage as efficiently as possible by dealing just enough damage to each enemy to neutralize it, and trying not to waste any extra damage that could be used elsewhere.


Damage Over Time in MOBAs

            The emergence of the MOBA genre has done a lot to highlight the possibilities inherent in the relationship between damage and time. Rapid bursts of damage may be the most surefire way to take down a rival champion, but ongoing damage can be equally deadly to the inattentive player. Even inexperienced MOBA players know to disengage when their health bar gets low, but if they only pay attention to the health bar and fail to keep track of DOT effects, it may already be too late. Attentive players are rewarded for their ability to track DOT effects and disengage in time to seek safety and healing.

            Delayed damage is actually one of the most important tools for MOBA design because it can be used to adjust the rate at which damage is dealt. Balancing a champion's damage output can be tricky. The main difficulty is the way in which damage scales between solo skirmishes and team fights. Dropping a champion to zero quickly gives the victim little or no time to escape or receive help from allies, so the effectiveness of damage grows exponentially as more and more heroes focus their fire on a single target. Healers are rendered useless and frustrated in team fights if it the opposing team's collective damage output allows them to take down champions before the healer has time to intervene.

            Now, the obvious way to optimize for team fights is to lower the damage output of champions, but this in turn has a negative impact on solo encounters between champions. If damage outputs are low, these encounters are long and inconclusive as assassin champions are unable to adequately punish enemies when they catch them alone and vulnerable.

            This is where ongoing damage can help. Abilities that deal some of their damage over time can be fairly potent, yet still scale gently in full team confrontations because the delay in damage gives the target time to retreat to safety and receive healing. Conversely, the delay in damage matters very little during small skirmishes where the pace of combat is slower and healers might not be present. Thus, damage over time can be used to make adjustments to a champion's performance in one class of encounters with minimal impact on his or her strength in other scenarios.


Turning Up the Heat

            The thing that got me thinking about damage over time in the first place was an idea I had a while back for an interesting take on DOT. Let's imagine a game were fire attacks don't deal immediate damage, but instead set victims ablaze by inflicting "flame stacks," which deal damage at each interval. The stacks decrement at a steady rate, so left alone the ongoing damage will taper off.

            However, the effect can be sustained and even increased provided you continue to hit the target with more flaming attacks. For example, a savvy pyromancer will open with a potent fire spell that inflicts a lot of flame stacks, then follow it up with a steady barrage of lighter flaming attacks to sustain the high rate of ongoing damage.

            I looked around for existing implementations of this mechanism, and I found Skaarf, a champion from the MOBA Vainglory, who comes pretty close. In Skaarf’s case, his abilities apply an “ablaze” condition to foes, which causes his basic attacks to apply damaging stacks and extend the duration of the effect. This means that the ongoing damage builds up slowly as Skaarf focuses a target, and drops off suddenly if the target is able to avoid his basic attacks for 2 seconds.

            Though each works a little differently, both of the above models are functionally “combo chain” mechanics. Users are rewarded for focusing a target and landing consecutive attacks, while their targets are encouraged to make periodic micro-retreats to clear the built-up stacks. The mechanic has a lot of play to it, which is why it interests me.

            Well, that’s plenty to think about. As you can see, damage over time is a rich subject. Even as I wrap up this post, I’m remembering some areas I forgot to touch on, so stay tuned for a possible part two.

Mechanics: Upgrade Systems for MOBAs

            When I sat down to write this post, my topic was going to be a comprehensive look at progression systems in MOBAs. Progression is arguably one of the central pillars of the MOBA genre, and shapes MOBA gameplay on a number of levels. My first draft ended up being quite a bit longer than I initially intended, so to keep this post to a reasonable length, I have decided to narrow my focus down to player-guided progression because it has to do with the initial inspiration for this post…

            Last April I was lucky enough to get into the closed alpha for Motiga’s maiden title, Gigantic. Now that the game has moved into beta, some of the NDA restrictions have been lifted, and I am finally able to gush about the game publicly.

            For those who have not heard about it, Gigantic is an action/shooter MOBA. As such, it uses a 3rd-person shooter control scheme instead of RTS style controls, and this opens up spaces in character and map design that are out of reach for traditional MOBAs. The game is gorgeous, and the controls handle so smoothly that I get excited just running around the maps. I could go on, but you should really just check Gigantic out for yourself.

            It was Gigantic’s skill upgrade system that made me take a closer look at guided progression. I already knew the basic theory behind MOBA upgrade systems; giving players a choice of upgrades lets them adapt characters to fit their own play-style and/or counteract the strategies, composition, and upgrade choices of their opponents. As you can imagine, the specifics of these upgrade systems do a lot to shape gameplay and deserve to be examined thoughtfully. Before we look at Gigantic’s system, I would like to lay some groundwork.

            When I look at the progression systems of popular MOBAs, I see two paradigms at work: “specialization” and “ordering.” The specialization paradigm asks players to make a series of choices between mutually exclusive upgrades, and causes heroes to become increasingly optimized for a specific role or play style as the match progresses.  The talent system in Heroes of the Storm is a perfect example of this paradigm.

            In the ordering paradigm, upgrade options are not mutually exclusive, and if the match goes long enough a hero can eventually acquire all or most of the available upgrades. As its name signifies, this paradigm asks players to consider the order in which they prioritize their upgrade options. DotA and its descendants exhibit this paradigm in their ability rank systems. These systems allow heroes to become specialized in the midgame by prioritizing one or two abilities, but ultimately builds will converge in the late game as players begin to max out abilities one by one.

            There are of course many systems that display a combination of both paradigms. Perhaps the most well known example of this kind is the item system employed by DotA and company. This system has specialization because a player can only equip a small subset of the available items, but the order in which items are purchased is flexible. Combining both paradigms like this adds another dimension to build planning and upgrade counter-play, since players must consider both aspects in conjunction. A player might go into a match with a build in mind. After seeing the composition of the enemy team, they may or may not change the content of their build, and even if their upgrade choices remain the same, it may be strategically correct to change the order in which they acquire their upgrades.

            Now, before I start talking about Gigantic, I should mention that the game is still in beta, and the things I describe could change in future builds. Unlike traditional MOBAs, Gigantic’s progression system is entirely guided; the basic stats of a hero do not increase as the hero levels up. The game has a small passive talent system analogous to the talent system in Heroes of the Storm, however the main emphasis is on the skill upgrade system. Each skill (hero ability) has a unique, two-tiered upgrade tree; a pair of initial upgrade options that each leads to its own pair of secondary options. This includes basic attacks (left mouse button skills) and ultimate abilities (though ultimates only have one tier of options).

            As you can see, this system mixes the two paradigms in a similar manner to an item system. The order in which skills are upgraded is flexible, and at the level cap (10) all skills are fully upgraded. However, upgrading each skill entails two upgrades to the exclusion of the others, so builds don't necessarily converge at high level. For a concrete example of how this works, I would like to introduce my favorite hero, The Margrave.

            As you can probably tell, The Margrave is a tank. This heavily armored pile of attitude comes equipped with a demonic arm and a pair of comically stubby legs. As a tank, The Margrave’s upgrade trees are designed to allow him to adapt to the particular offensive strengths of the opposing team.

            To give just one example, The Margrave’s right mouse button skill, Hellburst, is a channeled attack that doubles as a projectile shield. The ‘’left” upgrade path doubles the maximum channel duration, which is great against compositions with a lot of ranged damage dealers. Additionally, a second-tier upgrade in this branch causes projectiles to be reflected back at the attacker, which feels amazing when you reflect your opponent's ultimate back into their face.

            In contrast, the “right-hand” path radically changes Hellburst so that it no longer deflects but deals increased damage. This augments The Margrave’s mediocre base damage and helps him brawl with other melee heroes. One of the second-tier upgrades for this path causes Hellburst to slow enemies hit in the back, which is great for chasing fleeing enemies and peeling melee threats off your back line.

            Hellburst is just one of many skills in Gigantic that exhibit this wide range of functionality. I think that the developers at Motiga have really leveraged the possibilities created by skill specific upgrades, and it’s allowed them to generate a great deal of flexibility and depth in each hero’s build strategy on the back of a system that is remarkably minimal and elegant.

            I think that's a good note to end on. I will definitely get around to the other aspects of MOBA progression that I didn't have room for today. In the meantime, I will be dropping Hellbursts and generally sowing mayhem in the Gigantic beta test.