Limited Resources and PowerUp Design

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.

No top­soil, sure, but the trade­off is giant worms, mag­ic spice, psy­chic pow­ers, and FTL trav­el.

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.

Good luck find­ing the health potion, hoard­er

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.

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