Every time I think I've seen just about all that can be created in the way of innovative shoot-em-up games, somebody comes out with still another one with a different kind of twist. Crossfire is one of these and it offers the best of several worlds: quick reaction time, maze-type movement, gaming strategy, shoot-and-duck, street matrix layout and bonus creatures ready to be gobbled.

Graphically, the game isn't all that great, but the gameplay is so good that it more than makes up for this shortcoming. You're given three ships to protect a city from invaders, one ship at a time. You shoot by pressing the fire button and moving the joystick toward the creature you want to destroy. The enemy moves around the outside of the rectangular city and through the streets, so you have to watch out on four sides and duck down streets to avoid enemy fire. If they hit you or touch you, you're dead.

There are four bonus lights and one moves out into the streets after every 12 missiles that you've fired. Move your ship over them and you earn 100 points for the first one, 200 for the second and so on.

You have a limited amount of ammunition and you have to replenish it every so often by running over a special character. Also, as you get better and score higher, the number of shots you get per reloading will go down to increase the game's difficulty level.

You earn an extra ship for every 5,000 points that you rack up. You'll find that hard.

This game has a high frustration level and there's none of the good-natured humor that you find in other shoot-em-ups like Bandits. It's a deadly serious game and you have to get those aliens before they get you. Frustrating? You bet. But Crossfire also has lots of interest and staying power.

Shoot and duck out of the way immediately - before those nasties get your range.