The Juice: Megaman X’s Sub Tanks

by frangibility

Megaman X (1993) is great! It’s a superb example of Capcom at the peak of their 8- and 16-bit design powers, combining energetic music, expressive and whimsical sprites, creative bosses, and tough but fair level design. But rather than penning another paean to the game in general, I’d like to focus on one particular design decision that I think helped give the game a little something extra… the juice, if you will.


Previous entries in the series included special power-up items called Energy Tanks (or ‘E tanks’), which were typically hidden throughout the game world in locations that required some combination of precision platforming, keen deduction and/or unlocked Robot Master weapons to discover. Their function was simple: provide the player the option to refill their life-bar during the course of a particularly challenging boss battle or platforming section, which would potentially allow them to avoid the demoralizing appearance of a Game Over screen. In their earliest incarnation, using them was a serious strategic consideration, as they were single use items: once you expended an E-tank, it would never respawn or replenish, meaning that if you *still* failed to defeat the boss after expending one (a very real possibility if one was facing the Yellow Devil or any of the series’ other malevolently difficult robot foes), the only way to get it back was to restart the game (or re-enter a previous level select password).

In Megaman X, however, the developers tinkered with this formula with the invention of the Sub Tank. Though initially indistinguishable from an E-tank (given that they too are hidden throughout the game world’s various levels), upon finding their first one, the player quickly realizes that they are a somewhat different beast. Upon initial discovery, the item enters the player’s inventory (without any explanatory text) and sits there inert and unusable. With further play, however, the player will inevitably – at some point- run into a health power-up while their health-bar is already full, at which point they are treated to a previously unused sound effect, alerting them to the fact that *something* has happened. A quick glance at the inventory screen explains it: the previously empty bar in the center of the Sub Tank has begun to fill up. Once topped up, the player hears another new sound, signifying that the tank is now available for use.


Though a seemingly small change from the E-Tanks in previous franchise iterations, I noticed that it had two pronounced effects upon my engagement with the game: first, it provided a fun sub-challenge – namely, trying to get through the game’s levels without being injured, so as to fill up my sub-tanks as quickly as possible. In the process, it took a minor gaming annoyance (unusable power-ups) and turned them into an asset. Second, it also broke down a psychological barrier to using the tanks. As the type of player that typically makes it to the end of a game without ever making use of my best weapons or items (read: hoarder), the fact that these tanks could be refilled easily via good play not only lowered the stakes of using them, but also implicitly suggested that doing so was the intended way to play. Rather than being a crutch, they became another weapon in the arsenal. As far as I can tell, the only downside to sub-tank is that, when squaring off against a particularly challenging boss and failing repeatedly, one can be forced to visit prior levels in order to farm health power-ups, though in the right areas, this can be accomplished in less than a minute. Regardless, it is still much more forgiving than the evanescent, “one-and-done” E-tanks of yesteryear.


The gameification of power-up drops (through the creation of an additional “victory” condition), as well as the elegant, non-verbal manner through which this new game mechanic was explained to the player, were clever, thoughtful design choices. Though Mega Man X would certainly have remained an excellent game without this innovation, its inclusion took an already polished reinterpretation of the Mega Man formula and gave it a little extra juice.