"They" are not making commercial software for the BBC series any more but, as web sites and articles on unreleased projects' show, the machines' lives ended quite suddenly and left a fair few bits and bobs in production, too good for the shelf, that just didn't make it in time.

As X*L*C*R is a game that was originally destined for inclusion on Superior's nineteenth Play It Again Sam compilation (and did actually appear on the one new BBC disk released by ProAction), it had gained the blessing of the leading software house of the day and, although it was ultimately not to see production with them, this gives you some idea that it was never going to contentedly camouflage itself in the frequently drab colours of Public Domain.

As with some of the classic games of yesteryear, X*L*C*R is based around a very simple concept. You are Yu, a square spaceship viewed from the birds eye elevation, in the centre of an area of black space. Running through the square are numerous tunnels in L-shapes (although there are Ls flipped horizontally, vertically or both) and the object of the game is to position the square so that small beads, flying across the space either horizontally or vertically enter the square via them, are flipped through 90 degrees, disarmed and then exit it.

As the beads and openings are only the size of a Mode 1 full stop and everything is moving rather speedily, this is pretty challenging. Yet this is by far not the end of the story. After the bead has passed through the square, it changes colour and continues to bounce from top to bottom (or left to right) until it either collides with another bead or you get one of the shaded areas of the space-square in its path and safely destroy it. These areas again are only the size of the bead so get ready for some real pixel-perfect manoeuvering.

X*L*C*R is an arcade game for the hardened player and is very unforgiving with its arrest of your craft's energy level. You begin dead centre of the playing area and before long, one or two beads will begin to travel from one side to another, always either horizontally or vertically. If you miss getting one of them into a tunnel, you lose energy as it reaches the other side of the screen. If the bead crashes into the side of Yu, you lose energy. If, as the bead is travelling through the square, you press a movement key, the bead blows up and, yes, you lose energy.

The bites off the energy meter for all three of these faults are equally hefty. You can gain a bit of this back if any bead, whether disarmed by passing through the Yu or not, collides with another: whereupon the spot where they hit turns into a small energy x. But to move over it means the risk of not catching the next bead and, for the small amount of energy it contains, the risk of going for it is only really justified when the energy is already at crisis level!

To survive the level, you must accumulate a certain score. On level one, this is 100 points, on two 200, on three 300, etc. The winning strategy for doing this, based on X*L*C*R's tough rules, requires that you simply do not miss many beads. On the first level, this is usually simple enough (although you can get off to some unbelievably bad starts here too IF you're not concentrating) but from the next one onwards, the beads begin to come at you in twos, and then threes, then fours, fives ... suddenly you realise why X*L*C*R is sub-titled "Squiggly Snake II"! If you get more than one string of four or five beads smashing into the walls of the playing area, or anything else besides their friends, "You are dead" is printed across the screen and, um, you are dead.

As a piece of PD software, X*L*C*R is one of the most superb you could hope to find and is highly recommended for those foolhardy enough to entrust their attention and frustration toward it. On numerous occasions though, it does spoil for a fight. This is undoubtedly by by design and often occurs when trying to position the Yu's disarming tunnel in front of moving beads: Doing so towards the edge of the playing area only finds the disarmed ones bouncing in such a formation that it's impossible to get the destruction chamber in their path. Either that or these disarmed beads bounce and crash into the Yu before there's time to get it out of the way. Naturally, all the while, numerous others are doing their utmost to plot another course; one unhindered by your efforts!

As noted, the graphics are fairly simple but they are slick and work well. As this addictive anarchy is presented in Mode 1 too, they are multi-coloured and, through colour-switching, each level takes on a different look, with level six changing the background colour to a very challenging bright red! Sound is also impressive, with a jangly original music piece as background to the title screens (and another on the BBC Micro version accompanying the action) and a few bangs and bumps when the machine code collision routines get going. Michael Grant, the author, points out in the instructions that there's also a fanfare after level twenty - yet most players will need the luck of the devil to reach it!

Complete in itself in one machine code *RUNable file, X*L*C*R is right up there with Mirrorsoft's Tetris and Blue Ribbon's Trapper for lastability. Yet it achieves its addictiveness by sacrificing any compassion toward a player without a very clear screen to play it on or unschooled in the art of arcade gaming. Its penalty for almost catching a bead is identical damage-wise to a situation in which you hadn't tried at all, increasing both cries of "One last try!" plus the compulsory swear words and "Come on!"s. This niggle, with a title on the High Score page reading The Late Great XLC8 (Eight!) and the irksomeness of having the turn the tune off each time you play on the BBC aside, the game is great, and well worth adding to your collection.