For a game that informs you that it was inspired by the ZZ Top video "Rough Boy" the immediate audio-visual impact of Leviathan is quite surprising.

There is no sign of any of the ZZ Top trade marks - no leggy blondes in stockings and suspenders, no heavy guitar, or bearded geezers.

What you are immediately aware of however is still pretty impressive in its own right - an incredibly smooth-scrolling and detailed 3D landscape.

Leviathan's main selling point is the manoeuvrability of the ship and it certainly can twist and turn in all directions. It flips - just like the Manta in Uridium, only it happens in 3D perspective with very impressive animation. It can also roll sideways and attack the aliens at the same time, and move up and down as the game scrolls in and out of the screen as well.

The problem with all this flyability is that it makes the ship very difficult to control. You really have to master the eight different joystick movements that fly the ship. These are move left, move right, climb, dive, change direction left, direction right, speed up and slow down. Just as in a beat-'em-up, joystick control is all important.

The aim of all this scrolling shooting is to clear out all the aliens in three separate zones. You must destroy all of them within a certain time limit in order to progress to the next level.

The landscapes take advantage of the Amiga's superb graphics - really illustrating for the first time the quantum leap in quality between a graphically good C64 game (which Leviathan is) and a graphically good Amiga game.

The first stage is Moonscape with its crusty craters and a metallic blue surface, then comes Cityscape with futuristic buildings and satellite dishes and, best of all, there's Greekscape with statues and a silver surface colour. Each of these zones is stuffed full of vicious aliens. I counted at least ten different types. The most impressive of these are the Delta-shaped fighters and swarming coloured balls. One gripe with these aliens is that there is a certain place on the screen where you can fly and then pick the aliens off as they fly into the screen. This makes the game too easy. Of course you don't have to do this - in fact it's really stupid if you do because taking an alien from behind or from the side is much more satisfying.

Leviathan's flight information panel is pretty basic but at least everything on it works and serves a purpose. It includes a timer, number of ships left monitor, height gauge, fuel gauge, and enemy identification window.

The Amiga is desperately short of decent shoot-'em-ups so the launch of a new one is an encouraging sign. I can't help thinking however that the design behind Leviathan is just a little bit ambitious. It looks great and sounds OK but I can't see it keeping me up until the small hours.