After shooting baddies, rescue the survivors before they get sucked into the sun... or play something else.
Like most games of this sort, as you survive the levels, you see variants of the baddies. This one has about seven. The first baddies you see are pushovers, but as you progress, they can get a bit mean, as they'll begin maneuvering more evasively and also offensively, vindictively ganging up on you.
Graphically, it's the usual Vectrex quality vectors and everything looks good.
The sound is good. You've got the usual thrust sound effect, when you or a baddy explodes, and so on. You even get a nice short song at the beginning. In terms of gameplay, if you take the blast everything route, the game feels much more active. If you go for rescuing survivors, you've got to be careful with your shots and do a lot more maneuvering which gives the game a slightly different feel. The only flaw is slight and deals with the nuke. If it hits an enemy, it's fine. The nuke will detonate and hopefully take out a few baddies. If you mistake it for your regular gun, which I often do, the next time you hit the button, you'll detonate the nuke wherever it happens to be, essentially wasting it. It's nice to have the ability to detonate it and to have, but it can be difficult at times to use effectively.
This isn't a bad game, but it isn't particularly fun, or addictive, either. If you like these types of games, you're likely to gain enjoyment from it, otherwise, just let it go. There are others much more fun.