The aim of the game is to help Clyde exterminate all the unfriendly repulsive earth-riders slime. Clyde is a creature that comes from a distant planet named Blot, which was abandoned in order to reach a new home-planet, the Earth. In order to rid the new home of all the nasty creatures found, Clyde must collect the various potions which will buy him the weapons he needs. The main gameplay is rather simple including dodging, shooting and collecting small creatures to make a potion with. It is sometimes tricky to find the exact right spot to get your jump in. Fortunately, once you have conquered and progress to a next level, there is a shop waiting for you, in which you can upgrade your weapons and health status.
The game is no piece of cake though and that gives it lastability. This is thanks in to the torture screens which require a bit of problem solving rather than mere joystick dexterity to see you through. Those screens are quite nasty (and sick) I think, in which a single Blotian is about to be brutally tortured, but fortunately is you the one who can save him (well, if you find the right way)! If fail to save the little fella soon, then torture begins, and the whole scene is brutally (but technically, nicely) animated.
Graphics are pretty nice here and there are several more details than the original Commodore 64 version. The game has matured beautifully onto the Atari ST (and the Amiga). The ST version offers a great number of on-screen colors (using programming tricks) which found to be from 16 to around 45 in number. Both versions have equally good visuals and it's hard to find differences. I really liked the smooth background coloring here whilst sprites and other details are very well drawn too. Note that in the Amiga version, screen scrolling follows player's direction in contrast to the ST version which runs in flip-screens. Sprites move nicely too, and although there are a few slowdowns on the ST version, the game is very playable.
Sound is good too, having a nice introductory theme while there are several SFX during gameplay. The ST version support either music or SFX whilst the Amiga version offers both simultaneously.