Arcade Perfect

Racketboy.com did a pretty impressive article about shoot em ups (shmups) recently. I used to be into this genre in the 80s/90s but I haven't really played them much lately and I've been wanting to try to get back into them and play some modern titles.
This guide seems like a good place to start.
shmups-101-a-beginners-guide-to-2d-shooters