>So what is this game?
Touhou is a bullet hell game made by ZUN. Instead of ship or robots it features anime girls fighting youkai and such.

>Why isn't this in /jp/
This is a cirno board.

>Where should I start?
the games until 5 were designed for the PC-98 platform, which would require an emulator. It's recommended you start either with the sixth (first Windows game) or the second game (as the first one isn't a bullet hell) and work your way up from there
some games aren't your usual bullet hells but should be played anyway
1: Arkanoid
7.5, 10.5, 12.3, 13.5, 14.5: Fighting games
The others follow the basics of the bullet hell genre but usually add a game play twist.

>Where can I get the games?
http://www.moriyashrine.org/classic-era-th6th95.html
http://www.moriyashrine.org/retro-era-pc-98.html

>Touhou for bakas
https://m.imgur.com/s1JmZu8

>West Replays
http://replays.gensokyo.org/index.php

>Please git gud!
http://moriyashrine.weebly.com/introduction-to-touhou.html

>eraTohoK (plus other era engine games):
https://pastebin.com/6CULQcKd

>Touhou fangames (Unfinished)
https://pastebin.com/wGZuqr0q

DEMO LINKS:
Four seasons:
https://mega.nz/#!hIZTTapC!1A4MTSueiirqFTfLkMeSab3cd6B9b5s4uITU-DlUs2c

AoCF:
https://mega.nz/#!g4d0hRqS!cyFKIH3U_On3zUBNA6GtcIjNjrN3IK4StJBPalFafQM

Touhou is a game, and a manga, and a book, and music, but not anime.