Swoop, produced by Ambrosia Software in the 1990s for color Macintosh computers, appears to be a normal Galaxian clone. The formation of aliens bobs back and forth in space, occasionally sending dive-bombers after the player ship, while the player is tasked with thinning them out, one shot at a time. Swoop does add to the formula with an inventory of special weapons and items, obtainable by shooting down the Boss Galaxian yellow commander aliens while they are dive-bombing, and occasional dive-bombers granting score multipliers if they are killed before returning to their formation.
But what stands out the most to me is its selection of music. Swoop could have done almost anything for its soundtrack, evidenced by the four options available in the settings menu. "Minimal" generates the soundtrack on the fly for minuscule cost of RAM and system resources, and is advertised as being good for machines without much power. Swoop Techno... I'll be honest, I never set it to that. The one I always pick, and in fact the default for new installations, is identified as "Flight of the Parrots" from the Killer Tracks stock audio library. Except that's not the name of the track - or at least, it's not what the Killer Tracks website calls it.
Yes, Killer Tracks still exists (albeit these days they're under the Universal Production Music banner), and has a freely listenable online database of their songs. You can call up just about any old song out of their decades worth of music, if you know what to search for. And for years, I'd tried - "parrots" pulls up nothing. By chance I found the song's real (or current) name: "Between the Eyes." The portion used in Swoop begins about halfway in.
Ambrosia Software are noted for having employed the Killer Tracks library in a lot of their earlier games. Escape Velocity, for example, borrows a rather intense Fox Sports-esque track called "Face of the Enemy," while its sequel, EV Override, uses a more adventurous track called "Larry's Orchestral Adventure" (late-90s PC gamers might recognize it as also having played in the Studio 3DO game, Army Men). I've yet to identify any of the other ones from that era; I'm sure Apeiron and Barrack use other Killer Tracks, but I wouldn't have the first idea where to start looking - it's not like the online database is sorted by year.
[edit] Well, by accident, I did just find the title screen music for Apeiron; it's "Acid Test" from KT2: Broadcast News/Promo.