Spacer Shooter is exactly what you would expect it to be, and even a little more then just that.
+: It has some unique weapons too, like a black hole generator and a multi ally ship spawner that also act like shields. Also some power ups, like the missiles that spread out with your normal shots, seem unique too.
+: Upgrade system gives a nice RPG sort of feel to the game, and just gives you more reason to keep coming back. Also the campagin/story mode is twice as long to what I expected.
+: The short comical cut scenes and voice acting (even during shooting gameplay) give some nice variety to the game and gives the game nice character.
+: Survival mode is a appreciated addition to those who have nearly or have 100% beaten the game.
+: Visually looks nice on the PSP.
+: IT'S APPROPRIATELY CHALLENGING.
-: As to be expected, it looks blocky on the PS3 (though still looks good despite blocky looking sprites)
-: Cartoon style in the cut scenes may or may not appeal to some people, although this seriously isn't a big deal.
-: Can feel repetitive if you play it for too long in one session. (Levels also look a lot alike, except with some enemy variations...) (Also the upgrade system greatly helps with this obvious negative)
-: It takes a little time to get to an upgrade level you really enjoy.
-: Survival mode uses your upgraded ship in the story mode, so it sort of feels pointless to attempt it until you are at least close to having a fully upgraded ship.
Ok look, it's 2 dollars. (unless you're in Australia, then it's ironically $3.45...) It's a typical space shooter with some nice unique touches, it has an upgrade system that seriously, GREATLY, helps the replay value, and most importantly IT'S FUN, AND IT'S ONLY $2.
Buy it if this even if it slightly appeals to you.
It's not the best game I've ever played, by far it isn't, but this is an outstanding amount of game for $2 and you'll be hardpressed to find a game like this for $2