This prompted me to look up some more STG numbers.
XIIZEAL is sadly just at 1,822 ± 1,073
Very underrated game. Go buy it.
Crimzon Clover WORLD IGNITION is sitting at 98,210 ± 7,879
It has a few sales behind it, but still great numbers (for one of the best games in the genre on Steam it has to be said).
GundeadliGne at 45,544 ± 5,366
This is extremely cheap and was often bundled, so not really comparable.
REVOLVER360 RE:ACTOR at 40,907 ± 5,085
Mid-priced, but I
think it was also bundled once.
Jamestown is up to 613,939 ± 19,680
One of the earliest shmups on Steam I can remember, had a lot of hype going for it and quite a few bundle inclusions since.
A lot of games I tried to look up were filtered out by SteamSpy, in particular the stuff published by Nyu Media