Use the mouse for control. The ship will shoot in the direction you drag. Click the mouse to fire.
The game starts out simple, with two large circles that are drawn towards you as you play. You move the ship with the mouse, and holding down the left mouse button fires a stream of multicolored bullets. There's no hard time limit, but each enemy awards you points based on how quickly you defeat it. Don't take too long, or they'll start costing you points instead of awarding them.
The difficulty ramps up quickly as the game pits you against balls of varying size, number, and arrangement. On a few levels, you will run into indecisive squares who zip along in one direction for a while, then pick a new, random direction—often straight at you. If that's not enough for you, level 13 brings a twist that you won't see coming.
Ball physics come into play as the enemies bounce off each other and collide with your bullets. Though it's not obvious at first, enemies reflect your shots, which means that a well aimed shot can bounce off two or more of them, dealing damage with every hit. Unlike circles, squares are not pushed away by your shots, but their flat sides makes for easy bouncing. No matter which enemy you face, using your shots to their fullest is key to defeating each level as fast as possible, and can sometimes be the only thing standing between you and certain death.
At only 14 levels, Particle Blaster isn't as long as you might like, but it makes up for it with fast-paced, challenging gameplay. At the end, you'll be graded on your performance, so you'd better work fast if you want an A.
Of course, that's assuming you make it that far. I still haven't been able to finish the last level yet.