Xyanide took an age to find a publisher willing to invest in the Xbox version, but eventually was released at a wallet-friendly price, and it's worth a look. The game uses the twin-stick control method of Geometry Wars / Robotron for the main levels in which enemy ships can attack from all sides in the 2D plane. So fly one way with the left stick and fire another way with the right stick. Interestingly, as well as attacking from the edges of the screen, attack patterns also emerge from the background scenery, but will only start attacking once they reach the the same altitude as the player's ship (i.e. the 2D plane and signified by a glow around their ships). Depending on weapon mode, they can even be targeted and destroyed before they reach the attack plane. However, the boss battles are more like REZ in that they are part of the scenery, so you need to use missiles and target bits of the background whilst still keeping any eye on the things attacking in the 2D plane. It's a novel approach that only takes a few minutes to get accustomed to and once it clicks, it all makes sense and works really well.

The background scenery flies past on rails, although occasionally a branching path can be veered towards, with resulting benefits or impediments depending on route. The scenery itself is very repetitive and often quite dull, with the majority being dark industrial tunnels, or dark organic tunnels. It does swirl and dive and the camera viewpoint moves around too, so the player's direction is highlighted by a bright green glowing vapour trail. Similarly bright lighting effects are used all over the place, from the enemy ship glow, to the explosion effects, missile trails and activated power-up full-screen mutilation. However, in the main, the effects don't go far enough to sprucing Xyanide up enough and the overall impression is one of lacklustre visuals combined with a lack of variety. It doesn't help that even different enemy ship types end up looking fairly similar too due to the lack of primary colours (aside from the variety of glowing effects). In contrast, bosses are often spectacular, with a grand scale (often reminiscent, as said, of REZ bosses), retina-burning laser shows, lightning storms, burning wreckage and all the while, the constant onslaught of minion ships.

The weapons and power-up progression are also very unusual. There are two main types of enemy ship to contend with - large and small. The large enemies are dispatched quickly with the 'mechanical' weapon type and the small enemies should be fired upon with the 'organic' type. Right-trigger switches between the types, so they can't both be fired at the same time, making it interesting when both large and small are attacking at once. Pulling the left-trigger activates the missile targeting system, which shares the same dual-type properties as the main weapon ' organic missiles find targets themselves to a certain extent and mechanical missiles have to be aimed and allowed to lock-on with the targeting reticule (meanwhile, luckily your ship can still be manoeuvred out of harm's way). Picking up 'Xyanide' crystals, occasionally discarded by dispatched bad guys, powers up whichever weapon type (and associated missiles) is currently selected. Thus, there is a choice of balancing the two weapon types, or going all-out on one type. Power-up levels persist through death and even through continues, which is just as well since they build up very slowly. In parallel, a number of bonus weapons gradually get assigned to the face buttons. Once pressed, these time-decay until they run out and then take various amounts of time to charge up again. These vary from mirror craft that distract enemy bullets, through pheromone sprays that turn your foes against each other and on to full-screen laser carnage. This may all sound very complicated, but in the thick of battle, it's very easy to select the right weapon and escape almost certain death at the last second.

Xyanide has a far slower pace than most traditional shooters. Sometimes there are even a few seconds where there's nothing going on! The easy first level soon gives way to much more challenging attack waves in later levels, but still there is a lull between each wave. It's refreshing to have the pause for thought, and the game length makes memorising attacks almost impossible, so reacting as things happen is the only real way to play. However, these constant pauses between enemy attacks make the game excessively long. The whole game takes around an hour and half to progress through hence to get good and familiar enough with the levels to play through on one credit is going to stump most people. There is an incentive to keep trying though because Xyanide is Live aware and will upload your highest score to the online league table automatically. Scores bonuses are added on at the end of each level for various factors, but flash up too fast to really take in and the detail is not available on the scoreboards.

The presentation is particularly notable, with stunning cut-scenes unfolding the storyline in a fair amount of detail ' again an unusual choice in a genre that's usually devoid of plot unless it's in the manual. The ability to select your custom soundtracks is great, allowing the choice of exactly the right sort of music to get you fired up. Those with HD or Prog-Scan screens will be disappointed that it's 480i only though, but on the plus side, it's region-free.

Despite being an acquired taste and ultimately taking too long to progress, the combination of all these tactics, weapons and the gameplay style creates a game that's good fun. The control method really works and the attack waves are fair. There's satisfaction to be had from successfully juggling the weapon types and from dispatching the bosses in super-quick time, where missile accuracy is everything. The weapons and power-ups are imaginative and visually cool and the whole balance between 'organic' and 'mechanical' paths will keep you trying different combinations throughout the game. The action is great when it gets going and the bosses will bring a smile to anyone's face. Whilst disappointing in some areas, it does match its budget price point and in some respects even exceeds it. Worthwhile, especially if you want to try something a little different.