For the most part, it really delivers. The capital ships you fly are large, imposing hulks of metal that turn slowly and but are loaded with weaponry, shields, and armor. They are just maneuverable enough to make combat interesting; you never feel like you're flying about in a nimble fighter, but you have to pay attention to your positioning in combat. While most ships have a nice assortment of highly-effective turrets that can be levied against both fighters and capital ships (these were almost always set to auto-fire when I played), you also have an array of broadside cannons along each flank (think pirate ships!). Combat becomes a matter of maneuvering to keep your broadside pointed at a consistent flank of the enemy ships so you can whittle down his shields, while simultaneously avoiding his broadside cannons--not to mention the other half-dozen capital ships nearby, along with a dozen fighters all buzzing about. When the heat gets too intense, you can engage an extra layer of deflector shield, and use "afterburner"-style engines to boost out of the thick of trouble. Of course, your opponents have access to similar engines, and often will follow in pursuit. Combat effects--light, sound, etc--all just felt right. As the game progresses, I found myself immersed in epic battles between fleets of craft. I felt like I was in the battle of Endor at times, and that's the mark of a good space combat game, in my view.
Also, I should say a word about the soundtrack. Rather then the generic classical symphony we usually get in space games, they opted to take a big risk and went with a kind of garage band meets southern rock sound. As strange as it sounds, it really works, as the game tries to paint the setting as a sort of wild west in space. I found myself humming many of the games' tunes during the day, and sometimes would pull up the game just because I started thinking about the muscle.
Overall, this was easily worth its current $20 price tag. I put a good month into it, and I want more. If they posted a DLC story expansion, I'd grab it in a heartbeat. It sounds like the company is instead developing new games. If they ever decide to do a Rebel Galaxy 2, I will jump at it.