Chris over at Paper Dino recently put up a post on the lessons he learned from playing the Touhou shmups, e.g. Perfect Cherry Blossom and Imperishable Night. For those who don’t know, this is a series of shmups (shoot ‘em ups) made by one guy from Japan who calls himself ZUN. He’s iterated a lot on the basic vertical scrolling shooter formula and his shoulders are great ones to stand on when you’re making a shmup yourself.
Chris did an excellent job of highlighting several key lessons. Here are some of the things I took away from my own explorations of the series.
Almost all of the Touhou games I played had a button that, when you hold it down, makes you go slower. In the earlier Perfect Cherry Blossom you activate this mode by holding down the fire button, a’la DoDonPachi. In later games, however, ZUN remapped this slowdown to another button entirely.
One of the most subtle benefits of this slowdown is that it puts a small dot on your character showing your “real” hit-box. As Chris mentioned in his post, it’s usually a good idea in shmups to make the player’s hit box (i.e. the part of the player that, if it touches a bullet, will result in player’s death) much smaller than the image of the player’s ship.
Notice the little white dot on the player on the image to the right. That’s the player’s hit-box; as long as you remain in slow mode the game displays this point for you allowing for a highly technical level of play.
In most of the Touhou games the player’s main vulcan fire* is slightly different when slow mode is engaged. In Imperishable Night, the players main attack gets extremely different. As you can see on the right, the main character’s sprite also changes to reflect this.
With the character(s) pictured, the slow mode actually leaves guns behind in screen-space (the red circles above her are the guns) so you can put a gun down, for example, somewhere you know the boss often is while you’re off somewhere else dodging. By contrast, the main mode is a very traditional vulcan spread shot.
This allows for tactical decisions. All of the sudden you have an interesting choice of which gun to use for each wave of enemies that comes at you. Do you fire the spread to cover more screen, or do you leave a gun on one side of the screen to cover the other?
Imperishable Night makes this even more interesting by changing enemy behavir based on which mode you’re in. These things, called “familiars”, are usually spawned by bosses and shoot bullets at you. When you are in slow mode they won’t harm you by touch, but you can’t kill them either. When you are in normal mode, however, your bullets can kill them and they can kill you by running into you. This offers even more interesting play choices such as, for example, you choose whether to remain in regular mode so you can kill them and stop them from firing at you, or just to switch to slow mode and fire through them to get to the boss while dodging bullets.
The last mechanic that I’ll mention is the boss locator. Whenever you fight a boss, the word enemy appears on the bottom of the screen directly under where the boss is on screen (screenshot below). This lets the player see where the boss is with a minimal effort even when he’s busy dodging hell of bullets at the bottom of the screen. It’s a great innovation that’s particularly well-suited to the smaller bosses of the Touhou shmups. We may have to borrow this.
This is by no means all of the lessons these games have to teach. The bullet patterns alone could be the subject of a dissertation; I’m sure I’ll go back to that well. For now, though, these are my big takeaways from my brief research time. If you haven’t had a chance to play these yet I heartily recommend them, Imperishable Night in particular.
* The vulcan is pretty much the standard issue primary weapon in shmups. Originally named after the real M61 Vulcan cannon, the original standard gatling gun on American jets post WWII, in shmups a vulcan is a high speed, high rate-of-fire weapon.