Nice game and quite fun!
For example it has 2D parts that feel nice and classic, but you also have 3D parts that are surprisingly good for the playstation one.
One annoying thing is you have to watch out for bits of things flying around which can be quite hard at some points. Well I said its quite classic but instead of a plain and simple 5 lives, you have lives within lives which works quite well, as in space invaders when you loose a life it is really annoying, but if you have lives within lives its no worry.
The levels aren’t basic either there are space stations, planets and rocks in space that all give this game a more real and unique feel. the only thing I would say about the levels are that they repeat themselves, like on planets the same rocks and scenery will appear again and again ( mostly what you would expect from a playstation one game ).
The game has nice cut seines that are graphically good yet rather pointless, for example a little movie of the space ship zooming off to another planet. well yes, it fits in ( you need to know were you are going ) but it could be more interesting like a story or at least something .
The space ship you fly is quite basic, with a gun, some kind of special shot and it looks good enough.
Flying the ship in 3d can be quite complex and takes some skill, but its ok and works in this game.
I would say that if you are a fan of space invaders then this game is a must have, maybe some sci-fi fans will enjoy this game. Only if anyone sees this game for sell at a bargin you should get it.