The world is running out of oil. Clean water. Topsoil. Ozone. These represent serious resource problems about which I know … little. Do your research, and then shop or vote appropriately. On the other hand, a certain problem of digital limited resources has consumed much of my time of late.
First, let me refine my topic. I’m not concerned with game currencies: money, crystals, experience points, or ammo. Barring significant error, those resources persist through a game and remain valuable. With such in-game currencies, the designer makes an implicit promise to the player that currency will flow in (insert obligatory “the spice must flow” reference). Thus, the player might as well spend it, since he’s going to keep getting more. Games that break this promise are likely to be considered poorly balanced or frustratingly hardcore. How players spend those currencies represents major strategic decision-making, and the game incentivizes the player to acquire and spend currency for a variety of benefits. As a side note, virtual currencies have never been more important in games. They form the backbone of half of what constitutes game design going on right now.
In any event, currencies aren’t what I’m focused on. The game I have in development has made me curious about tactical decision-making (as opposed to strategic). How and when do players use items and abilities that we broadly call power-ups? In this category, I’m including consumables, grenades, buffs, cooldown-based abilities, limited-use weapons, special ammo, etc. Regardless of the incarnations in an individual game, I want a better understanding of how players choose to use their items and abilities. What triggers the decision? That’s a question I’ve been discussing with players, developers, and playtest victims. How to best design power-ups for our games?
A core problem with power-ups is there is no guarantee of resource replenishment. Barring the use of a hint guide or online walkthrough, the player can’t predict when he or she will find a power-up. The player can’t make informed decisions. In more competitive multiplayer, the player may learn where objects spawn, but perhaps not when, or if they have been claimed. So, point one about good power-up design should be: keep the player as informed as the game design will allow. Try to introduce greater reliability.
A similar lack of prognostication obscures when to use a power-up once acquired. The game’s narrative, if such a thing exists, can provide clues that “this is a high challenge moment.” That can do the job, to be sure. And if the power-ups only exist in order to be activated during boss fights, so be it. The downside? The more explicit we get here, the less agency we’re reserving for the player. If a challenge explicitly calls for power-ups, and is balanced to assume power-up usage, what have we gained?
So, an essential problem is the player has an incentive to hoard power-ups, like some unfortunate creature from the reality tv show of the same name. An imagined challenge always lurks in the hazy future. So consumables pile up in the inventory, often languished until the end of the game. How to stop hoarding? Here’s the irony. Ask any player, and they’ll tell you they need more inventory space. Many roleplaying games embrace this, creating an economy in which players spend currency (even real-world currency) for the privilege of more inventory to manage. Hmmm.
Back to design. So what is the point of power-ups? Is the value in finding them, or using them? If the acquisition is the end, the specifics of how we use or store them is barely relevant. Why use power-ups as pure reward? We have other, less utilitarian, devices for that — hand out experience points, game currency, cinematics, or achievements. Power-ups allow a player to become more powerful than the game balance generally allows. To exceed normal limits. In as much as the game design supports choice, a power-up represents a chance for the developer to make the player feel like his choices make a difference. For the player to demonstrate his intelligence and mastery of the game.
If large inventories present twin dangers of hoarding and interface nightmares, simplification offers hope. My playtesting is showing that with tight inventory maximums, players use more power-ups. At the far end of the design spectrum: a max inventory of zero. Players activate power-ups in the act of finding them or walking over them (e.g. the Mario approach). It solves the problem, but it does takes away most of the decision-making. A player can remain adjacent to a power-up until it is needed, but this confines player behavior to a great degree. Good for some games, especially more casual games.
What’s next after an inventory of zero? Well, one. Left 4 Dead offers a solution revolving around an inventory of one for offensive power-ups (grenade-like objects) and defensive power-ups (health packs). Inventory remains visible onscreen and hence obvious at all times, confronting the player with options to recover health (with voice-over reminders from AI) or throw the dynamite (with audio cues from fast-paced action music).
After one, we arrive at few. The best solution I’ve found along this line is in the now-classic MMO, City of Heroes. The “inspiration” system remains onscreen and presents a reasonable number of options to the player without significant inventory management. The temptation, though, is to save valuable inspirations (such as “awaken”). And even at the low levels when the inspiration inventory cap is small, players hoard these power-ups, waiting for the perfect moment. Which never comes. Unless it’s a heal or resurrect. We do seem better, as players, of responding when defensive power-ups should be used. A low health bar is an easy stimulus.
Offensive power-ups need more thought, and we may need to abandon the inventory metaphor altogether.