Keeping Your Game Tactical: Volume of Content vs. Volume of Interactions

Okay, I admit, one of the themes of this blog seems to be me making up terms so that I can explain myself, and I just did it again, but this is a seriously undervalued concept, and I don't know if there is formal game design language to discuss it.

Also, this is meant to be a follow-up to my previous article, so if you haven't already, I recommend you read that first.

Okay, now on to the definitions.

Volume of Content

Consumers want lots of content. And game developers try to meet that desire by building new environments with new enemies with new mechanics.

On some level, you have to do this, but there are problems with using this as the primary way to create continuing interest and variety for your players.

1. Encourages Patterns Rather Than Tactics: As described in the previous post, a new boss with a new set of mechanics doesn't really require players to think tactically. They just need to learn a new pattern. Once you figure out the basic techniques, fighting this enemy is just as much a routine as fighting any other.
2. Scales Poorly: Twice the variety in your game means twice the assets. Given how fast many players consume content, it takes a huge amount of resources to keep players interested in your game for any length of time.

Volume of Interactions

With this approach, you look less at the number of enemies or game elements that have unique mechanics and more at the ways they can be combined. Let's give a concrete example from a genre that's usually fairly good at this:

Picture a shooter game with the following enemies:

Heavy Gunner: Slow to start shooting but does devastating damage. Typically, you have to step out of cover, take a few shots, then dive back into safety before they open fire.

Berserker: Charges your location and clobbers you with melee attacks. You have to shoot him a lot on his way in or he'll probably kill you.

Two enemies, two patterns, right? Wrong. What if you're fighting both enemies at the same time? The tactics that defeat one lose to the other. There's no obvious right answer anymore, so you're going to have to look at terrain, your character's special abilities, or other details to find a way to solve the problem. A new challenge was created by combining two pieces of existing content rather than adding anything new.

Advantages to this approach

1. Lower Asset Requirements: Sure this is obvious, but the degree to which this is true is greater than you probably realize. If you have 10 unique enemy types, there are 45 combinations of two, 120 combinations of three, and 420 combinations of four. Obviously not every combination is going to be fun or interesting, which will reduce your count, but on the flip side, these are only combinations based on number of enemy types. Other sources of interactions built into your game (terrain, character designs, group interactions, etc.) will multiply this back out.
2. Tactics over Patterns: Players can easily memorize a couple dozen patterns over time, but most can't memorize hundreds. Instead, they have to adapt and make different decisions each encounter. You now have a game that requires actual strategy/tactics instead of one that claims to but is really all about following routines.
3. Scalability: Suppose you release an expansion that adds 2 new enemy types to you existing 10. With a Volume of Content approach, you've expanded your game by 20%. From a Volume of Interactions approach, it's harder to say exactly how much, but here's one number to give you an idea. With 10 unique enemy types, there are 420 combinations of four (as mentioned above). With 12, that number goes up to 990.
4. Reduced Learning Curve: Each unique enemy or mechanic requires the player to learn something new about your game. On the other hand, each unique combination of familiar enemies/mechanics requires intelligent problem solving using knowledge the player already has. This is one of the ultimate paths to the oft-sought "Easy to learn, difficult to master" concept.

Mechanics that Interfere

Taking an existing game that took more of a "volume of content" approach and combining existing elements likely won't give you the results you want. If you didn't build the game planning for volume of interactions, you've likely created mechanics that don't work well with it. Here are some examples:

1. Binary Choices: I plan to give this its own article, but I'll give a single example here: Suppose an enemy has a mega attack that you must dodge or die. That simply means that every tactical choice goes on the shelf whenever this attack starts because allowing yourself to get hit is never the right option. Replace this with a powerful but survivable attack, and the player now has options to weigh ("It's going to hurt, but my health bar is full, and I need to keep blocking this hallway while my teammate recovers").
2. Enemies that are too Similar to Fight Against: If the skeleton archer, the orc marksman, and the venom spitter all require the exact same approach to defeat, then the three only provide one unique enemy from a tactical perspective. Of course, having all three can add value to your game for other reasons--it just doesn't increase tactical depth.
3. Enemies With Too Many Mechanics: An enemy with several different abilities may make a more interesting opponent when on its own, but if you start combining complex enemies in a single encounter, you end up with less of a deep tactical challenge and more of a big blur, especially if it's hard for users to look at the battlefield and judge what's actually happening. Instead, you want most enemies to have a small number of mechanics that are easy for the player to see and understand.
4. Excessive Stat Inflation: Do players choose their weapons because of their unique characteristics or because of their really big numbers? A good game to analyze for this principle is Borderlands, where a given weapon can vary on several different parameters (zoom distance, attack spread, etc) to the point where even two different sniper rifles may favor different play styles. The loot and choices you make for your character will give him a unique toolkit and vary your playstyle and available tactics. On the other hand, sometimes you find a weapon with so much power that you just ignore your other choices and use it all the time. A great approach can be to have enough stat growth to encourage the player to change weapons occasionally but not so much growth that they just always chase the biggest numbers.
5. Ease: Tactics are only meaningful if they affect your outcome. I have quit multiple games that people claimed were highly tactical because they were actually quite brainless. A big list of spells, units, or other elements is just aesthetic if you can succeed by making any semi-intelligent decision. Perhaps after X number of hours of play, tactics become necessary, but games that hide the interesting stuff behind hours of tedium are a tangent that I want to address in a different post (it's a complex topic).

A Few Examples

Chess: One map, six unique pieces with very simple rules, and no configuration options. And yet we have one of the most tactical games of all time because of how the pieces interact. But you probably want some video game examples, as well, so I'll move on to those.
Kingdom Rush Series: As far as tower defense games go, these are the best I've found. Each game has just four basic tower type that each split into two variants when you upgrade them enough. Even when it uses similar enemy types, each map is a fresh experience because the new options for tower placement and the combinations of enemies always require you to develop a different approach.
Dead Cells: 2 weapons, 2 utilities. And it's a roguelike, so your exact available configuration varies among playthroughs. None of the items are particularly complicated, but they can play off each others' strengths, cover for each others' weaknesses, or offer novel ways to defeat enemies, so the exact combination is important in how you will tackle each challenge. The end result is a hack-and-slash side scroller with a lot more tactical play than you'd usually see in that type of game.
Customizable Card Games (esp. Draft Pick): CCGs are an interesting case because the volume of interactions concept is key to the genre, and yet they can span both extremes of patterns and tactics. It is usually the case that your deck is much more important than your in-game decisions, which makes it look like it lands much more on the patterns end of the spectrum. However, as long as you aren't somebody who just looks up top tournament decks and copies them, you will probably be constantly adjusting or reworking your decks, pushing it more in the tactics direction. Draft pick modes will usually be the most tactical as you have to always be figuring out new combinations and just can't go into autopilot mode as you might when playing the same deck for the 50th time.

Final Thoughts

If you are trying to sate your players' desires for a tactical game while providing them an experience that stays fresh even after hundreds of hours, this is one of the best ways to do it. Simple components with complex interactions can have incredible staying power.