The 1-Pixel Collision Box

In the early 90s, a trend developed among shoot-’em-ups that was affectionately (or was it rancorously?) dubbed “bullet hell.”


An example of bullet hell. It gets worse. Much worse.

The impetus behind it was to add visual flair to 2D games in order to compete with the craze surrounding 3D games. Arcade cabinets were more powerful than ever before, so these shooters could handle many more sprites and the extra calculations required for the accompanying collision checks. The approach worked relatively well, providing plenty of “Holy Shit!” moments. However, there was one major issue: playability.


Ikaruga's dual colour scheme was the focus of its gameplay.

Shoot-’em-ups tended to be one-hit kill games, and simply saturating the screen with harmful projectiles made them incredibly difficult (if not downright impossible). Now arcade games are meant to take your money, but that wouldn’t happen if no one played ’em. In order to implement bullet hell without alienating customers, something had to give.

Part of Ikaruga‘s solution was to make all bullets and your ship one of two colours, and then simply ignore collisions between like-coloured objects. Other titles used shields and various powerups, but the original solution, and, in a way, the purest to the genre, was the (roughly) 1-pixel collision box.

Instead of surrounding the majority of the player’s ship with an area susceptible to fire, a single pixel was used to indicate its vulnerable spot. This was a rather elegant solution as it required no other changes and didn’t present an extra hit to performance. Players were also less likely to feel cheated if they came out on the positive end of some collision-fiddling. The end result looked something like this:


Saint Dragon's eponymous lead actually looked pretty good in motion.

The visual oddity of having the player’s ship fly straight through harmful projectiles was lessened by the nature of the top-down perspective. This view had issues with representing depth/elevation, and that actually made it easier to imagine bullets just skimming over the player’s ship. The 1-pixel collision box also had the side-effect of making the player feel more skilled at the game, which — in the very least — provided the illusion of empowerment.

As a side note, something of a similar concept was used in an old Amiga shooter called Saint Dragon. The player’s ship, the eponymous Saint Dragon, consisted of a head and spiraling tail. The head used regular collision detection, but the tail was purely aesthetic. This added scale and personality, and allowed the player to control a vehicle that seemed grandiose despite being virtually identical to countless other shoot-’em-up ships. The head could be easily destroyed, but the tail would actually absorb many types of bullets and even damage most of the enemies it touched.


Since I’ve posted this article, it’s gotten a lot of attention from numerous shmup enthusiasts. Many have been eager to bring up the specifics of the tiny-collision-box phenomenon, as well as variations on the theme. I think that’s great, and one of the sites that has been pointed out to me contains a lot of interesting information on the genre. Of particular note are its threads on shmup strategies, the dos and don’ts of good shmups, and the glossary of common shmup terms.

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Deductive Puzzles

Adventure games are filled with their fair share of sleuthing, so why do they often turn into a parody of MacGyver?

Well, gameplay, of course. Browsing the scenery for usable objects — whether they can be picked up or not, and whether they can be used by themselves or in conjunction with other objects — is the interactive cause-and-effect bit.


Way too many designers have asked themselves that very question.

Considering how many adventure games revolve around solving mysteries, though, it’s surprising that so few of them rely on the player’s deductive skills. Instead, the audience is often stuck doing all sorts of illogical things, especially on a micro level. There’s usually a clear goal, but getting there is a matter of figuring out the logistics, not the mystery.

Now relying on the player’s deductive skills can be a big challenge. It’s not the most casual concept, it can be difficult to keep all the details of the “big picture” in one’s head, and even small discrepancies between the player’s conclusions and the designer’s intentions can result in an impasse.

Still, it’s not impossible.

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Orange Box Designer Commentary

Valve first tried out designer commentary with the Lost Coast standalone demo. Apparently it was such a big success that they decided to do the same for all the games in the Orange Box.

Now Valve is a group of some very, very smart people, and it shows.


Escape from City 17 at the end of Half-Life: Episode One.

Generic behind-the-scenes specials tend to tell the same old story: the development cycle was hectic, but the team eventually persevered and released a great product (even if it was a little flawed and missing some features). In between all that you might come across an interesting tid-bit or two, but don’t expect any mind blowing revelations.

The commentary on the Orange Box, though, is full of pure-gold nuggets. In fact, playing through its four commentary-enabled titles will probably teach you more about various aspects of videogame production than any game design book. If you haven’t checked it out but are in any way interested in videogame design, I urge you to do so now.

Here are just a few segments I picked out:

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The Greatest Collectible Of All Time


One of the famous coin arrows in Super Mario World.

In-game collectibles are a staple of platformers and play a big part in various videogame genres. They help to fill out maps, provide points bonuses and aid the player in overcoming the game’s challenges. They also flesh out the setting, sometimes even being used as part of its architecture, e.g., the coin-arrows in the various Super Mario games.


Apparently all clocks in Final Fantasy VI are secretly powered by elixirs.

Collectibles seem to speak to the kleptomaniac side of our personality, encouraging us to take all that we see. In console RPGs, it’s common to break into people’s homes, rummage through their belongings, and generally pillage the entire world that you’re trying to save.

And why not, really? After all, as players we want to be rewarded for exploring. It’d be awfully dull going from one empty room to another, so letting us interact with the game as if it were an episode of Supermarket Sweep might not be such a bad idea.

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The Magic of Secrets

All sorts of entertainment media use the concept of secrets to add intrigue and evoke a powerful emotional reaction. A strong effect of unveiling a secret can be the validation of the observer’s perceptiveness and reasoning; a wink wink, nudge nudge for being such a smart cookie.


Grand Theft Auto - San Andreas' Hot Coffee mod. Despite the scandal this polygonal sex caused, it was not a real videogame secret.

However, most forms of media tend to be strictly passive. Aside from the occasional dabbling in interaction, the audience exerts no direct influence over the medium’s content.

Games — and videogames in particular — are inherently different. They are interactive and require players, not just observers.

There are plenty of lists online cataloguing the “best secrets in videogames,” but before we delve into this discussion, let’s actually define the term:

Secret, n.

  1. Something kept hidden from others or known only to oneself or to a few.
  2. Designed to elude observation or detection.

Now let’s apply this denotation to design in videogames.

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