I personally think (and deeply feel) that music is a powerful resource when it comes to make a game memorable; in short because it makes people feel many different kind of emotions which can drag you deeper into your gaming experience.
I found an old post about suggesting a top 20 (or 25) best OST from shmups, but what I intend to do here is more like a game: Every post you make should contain just ONE link to ONE track from any shmup which you find interesting for any reason and you want to share with this community just for the sake of sharing great music. Please, don't forget to always include the names of the shmup and the trackl; if necessary, the platform or version it belongs to as well.
Maybe this post turns out to be an alternate way to get to know more shmups too!
Having that said, I'll start.
This one here brings me back to my childhood days:
U.N. Squadron (SNES): Mission 1 - Front line base
Damn sweet composition!
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EDIT:
Since this thread is getting some interest I decided to put all of the tracks posted into a YouTube playlist for you to enjoy anywhere you can!
I'll expand the playlist everytime we get to complete a full page in here (Or ultimately when the thread dies

Thanks to everyone for making this possible and keep them coming!
The SHMUP music sharing game PLAYLIST
**At the moment there is a couple of tracks I couldn't add to the playlist since they're not YouTube links, here:
Valkyrius - Steel Titan
Fly to The Leaden Sky (Battle Garegga) metal arrange by Warinside
Koutetsu Yousai Strahl, by UP (I loved this one!)