http://www.youtube.com/watch?v=3AHhkq7p3Qw
http://www.youtube.com/watch?v=Fv7fCr6QFis

Two very neat things from many bullet hell shooters, including Touhou games, that you didn’t mention:

Some games give bonus points / firepower / etc. when you “skim” bullets. This means that if a bullet hits your ship but not the collusion box you get extra points, etc. Some games even actively encourages you to put yourself in harm’s way if by offering extra score multipliers that can only be earned by getting “hit” like this.

Many, many games also offer a button that lets you slow down your ship and makes the hitbox visible. It reduces your speed but makes dodging many things easier. Some games also alter your weapon when this button is pressed; most often your spread attacks become concentrated so you can stay under a boss and shoot it with all you have. By enabling this mode you really focus only on the area next to your ship and to do well in a lot of these games you need to shift your focus seamlessly between normal, spread out, kill everything mode and focused dodging mode.

As for Ikaruga, I simply mentioned that it used a flipping mechanism in tandem with the colour-coded bullets, not that it was the first example of 1-pixel collision boxes. After all, the idea of bullet-hell (as loosely defined a concept as it is) is popularly attributed to Batsugun and all the subsequent Cave shooters.

Now collision boxes themselves never wholly encompassed the player’s ship’s as that’d be incredibly frustrating. Instead, they were always catered to the ship itself, and yes, sometimes they were quite small. However, from what I noticed, they were never shrunk down to just a 1-pixel box until the arrival of bullet hell shooters.

The concept of the collision box “filling up” or completely encompassing a projectile is new to me, though. And yes, you’re right, it would behave differently. For example, a bullet heading down-right over the player’s ship could overlap a large portion of it, including its center, without being registered as a hit if the far right side of the ship’s collision box was not touched. This would mean that unlike 1-pixel boxes (which always register a hit upon being intersected/overlapped), these “full boxes” would allow bullets to virtually pass over every part of the ship without hitting it.

Interesting. Thanks for the info/link.

I don’t think the hitboxes being too big was ever a major issue, either, except among developers that were terrible at making these games. And I would not go so far as to say which came first: the bullet patterns or the hitbox, because the two concepts work so closely in tandem with one another that they were probably conceived simultaneously in, again, a natural way. Some developers probably thought, “How can we keep players playing longer?” and the solution was “Make it harder for bullets to hit them, so it feels more ‘fair’” and then the concern would be “Wouldn’t that make the game too easy?” and the next solution would be to add more bullets.. But it also probably just as often went the way you said, where they were looking to add more bullets, and felt they had to reduce the hitbox size out of fairness.

Also there’s a lot of nuance to this idea, too. Most of these hitboxes aren’t literally a single pixel. Also sometimes (oftentimes?) the hit detection works in different ways, like a bullet needs to completely fill the hitbox in order for it to register a hit, rather than just touch the edges or overlap (it might seem like a minute difference but it causes the game to play a lot differently, and makes the hitbox itself feel more nebulous and uncertain).

If you can tolerate the elitism, go to the shmups forum (http://shmups.system11.org/) and try reading a scoring/strategy guide and you can see the variety and depth to these games. Most game designers probably would not want to delve to deep into these ideas, because they are very niche and don’t have very wide appeal, but I think it’s nice to know that the ideas are out there.

I guess this is all just nitpicking but I hope you welcome this level of rigor in observations about game design.

My bad.

As you can see in this video at times: