Before each level, you can improve your ship and choose from huge amount of weapons and fancy upgrades. Once you start the level, hell breaks loose. A visual firework of ships, rockets, lasers and of course, massive explosions!
But the best of the game is the powerful soundtrack, made by Machinae Supremacy. It blends perfectly with the game and raises the urge to destroy things. Exactly what you do in this game
Have a look at the game, a demo version is available from http://jng.rakeingrass.com/
The soundtrack can be downloaded standalone from the Machinae Supremacy website: http://www.machinaesupremacy.com/discography.htm Check out their other music too!
Here are two screenshots, but they cannot possibly capture the spirit of JnG:
