Classic sidescrolling shoot-em-up action!
In Stargunner, two intergalactic civilizations are at war. You're an elite pilot from one faction on a mission to stop the other... and that's pretty much the story. Seriously, you don't play these types of games for the plot, do you? It's all about blowin' stuff up!
As far as scrolling shooters go, this title is average. Prior to each stage, you can upgrade your ship with new gear, and the end of each level features a boss fight. There's a few things that make the game fairly challenging - namely that you can die by touching the terrain (ala Silver Surfer, NES) and you'll often get surprised by some cheap stuff that is far less avoidable the next time you play.
The real disappointment with this game is that it offers nothing new to the genre, and didn't even when it was new back in 1996 (Tyrian did just about everything this game does, but better, and was released the year prior). Much like the classic Contra, this game has a spread shot that is objectively better than the other primary weapon powerup.
I know I sound really critical of this title, but in all it's not terrible. Stargunner does get a lot right by sticking to tried and true staples of the genre. It's a competent shoot-em-up, but don't expect to see anything unique here.