Gensokyo no Nazo is a Touhou fan game released for the PC in 2012. It is the sequel to Touhou Yuuen Sekai, featuring similar gameplay and more than twice as many playable characters. The intro cutscene contains all of this game's story. It explains that doors have appeared across Gensokyo and shows Reimu and Marisa, ready to investigate the issue.
Gensokyo no Nazo is a 2D platformer which sends the player across differently themed areas, defeating different enemies, collecting chests that may contain lives or points and fighting the bosses of each area. All areas contain a varying amount of stages, which are connected through doors. Sometimes these doors are hidden and can be revealed with a basic attack. Defeated bosses become playable characters. The game ends when you defeat the boss in stage 200, but you can continue playing after the credits and access a bonus area.
All characters have a different movement speed, jump height, weight (which makes them descend at different speeds), and hitbox size. On top of that, each character has a unique set of magic abilities as well as a unique basic attack. Players can change their characters at any time by bringing up a menu in which they can also spend lives to revive dead characters. Once all lives are used and all characters are dead, the game will show a game over screen and go back to stage 1 with all characters revived and the three lives.
Some characters have unique abilities, which make them useful in certain situations.
- Remilia and Flandre Scarlet: Both continuously lose health in sunlight, so avoid using them in stages where the sun is visible. They cannot die from this effect.
- Yuyuko Saigyouji: She gains health from killing enemies.
- Rumia: She has extended vision in dark stages.
- Yukari Yakumo: Opening the character menu while holding jump with her will teleport her to the next stage in numerical order.
- Keine Kamishirasaw: She can hurt enemies by jumping into them from below.
- Eirin Yagokoro: She has the only ranged basic attack in the game, making her the only character able to hit switches from a distance.
- Kaguya Houraisan: She regenerates health while not being used.
- Fujiwara no Mokou: She regenerates health while being used.
- Aya Shameimaru: She can walk on clouds.
All characters have three different magical attacks, a basic attack and a charge attack.
Magic abilities are used by pressing or holding the Shot key. Holding Up or Down while using a magic attack will give an alternate version or a different magic attack. Using magic costs spirit points which are regenerated while the Shot key is not being held.
Basic attacks are executed by pressing the Attack key, they are usually melee attacks that are often strong, but risky to use because of their short range. It is possible to move while using basic attacks.
Charge attacks can be executed by holding the Attack key. The longer the key is held, the stronger the attack will be. Each charge attack can be charged up to three times. Using charge attacks costs RP which do not automatically regenerate.
There are five different items that can be found or dropped by enemies.
L items restore a character's health points.
S items restore a character's spirit points.
R items restore a character's RP.
L, S and R items come in a small and a big variant, which give different amounts of points.
F items revive and fully restore every character. These are only dropped by bosses.
1UP items grant a life. These are only found in fixed locations.
Picking up orbs provides a permanent stat boost to the currently selected character. There are five kinds of orbs:
Red orbs, which upgrade a character's maximum health.
Blue orbs, which upgrade a character's maximum energy.
Green orbs, which have different effects for each character and can upgrade anything, for example a character's jump height, the strength of magical or basic attacks, a character's resistance against certain elements or a character's special ability.
There are also flashing versions of the red and blue orbs, which provide weaker effects of the same kind to all characters, including ones unlocked after the orbs are picked up.
Chests come in bronze, red, silver and gold variants. Higher grade chests give more points and are usually more likely to contain extra lives, but some chests will always contain lives.
Besides the arrow keys for movement, there are five controls: Attack, Jump, Shot, Pause and Escape. By default, these are bound to Z, X, C, A and S. Navigate menus by using Attack to confirm and Jump to return to the previous menu. The Escape key can be used as an ingame alternative to any keyboard's escape key. In this menu are the options to resume playing, open the map or quit to the main menu. The Pause button will bring up the character selection screen. Saves can be deleted by selecting them and holding the Delete key for about three seconds.