Unfortunately it wasn't to be and Syphon Filter 3 released on the PSX in the year after the PS2 was launched. After that there was even doubt that there would be another Syphon Filter game at all and things went very quiet for some time until information started to leak out that something was in the pipeline. That got us all excited again and after nearly three years of waiting and hoping, Syphon Filter: The Omega Strain has just recently surfaced on Sony's now-aged black box.

Fans of the series will readily recognise some similarities to past games but everything's obviously looking a lot more next-gen this time around with an upswept graphics and physics engine and some huge and quite interesting maps. The initial disappointment some may feel at not being able to again play as main Syphon Filter character Gabe Logan, won't last long either as there's now the ability to create your very own custom-built agent.

This is done via a Tony Hawk's-style feature that allows you to customise many facets of your in-game character. There's a decent range of options to start with but as you play you unlock a mountain of extra bits and pieces that can be used to further customise your agent as you go. Hats off to developers Sony Bend for including this as it really adds something worthwhile to the title.

Storywise, Omega Strain pretty much picks up where the series left off a few years back but there's been a few changes. The secret anti-terrorist organisation known as the ICPA now reports directly to the President and is headed by Gabe himself. You now play a newly recruited member in the elite team he manages but the script pretty much follows the old "track down the bad guys with the deadly bio-weapon before they kill us all" line. In this respect the storyline is quite clichéd and has been done-to-death already in many other action games (including the three previous Syphon Filter games). Also it means that gameplay largely revolves around heading to waypoints to activate switches while fending off waves of heavily armed opponents.

Actually, the story is probably deep enough overall to be quite interesting, if not a little confusing at times, but you get the picture. What has changed quite a bit though is the structure of gameplay and the way in which you play through the levels. Instead of implementing a traditional checkpoint system and tightly focussed levels where you strategically take out enemies and progress on, The Omega Strain chucks you into huge sprawling environments where you have to continually fend off respawning enemies as you roam around trying to learn the lay of the land.

Exploring the expansive maps can be fun but when it comes to beating the par times for each level in order to unlock the four extra missions and bonus items it can be damned frustrating the first few times you attempt to suss out the most effective routes. On top of that the save system will dump you back at the last point in the level where you achieved an objective when you die with only the same ammo you had left and you then have to fight your way through all the respawning enemies again. This keeps the story moving along uninterrupted but leads to a lot of repeated hollow battles in order to progress.

What this means is that before you get to know the map really well you can expect to take four or five times longer to complete the levels than is required for a par time. Even when you do know where every shortcut is it can still feel like an impossible task that'll take repeated attempts so there's definitely no shortage of challenge here. Also if you miss out completing any secondary objectives and par times that unlock the extras then the only way to redo them is to play through the level again from the beginning, but in The Omega Strain there is no option to restart the level mid-game. Instead you have to quit and go all the way back out to the main mission selection screen and sit there while it reloads from the beginning, something that could have been handled a lot more efficiently.

All this sounds like it could end up driving you nuts after a while and you'd be right if you really hate having to replay levels repeatedly just to get through the game. The reason this gameplay mechanic was adopted becomes apparent when you realise that The Omega Strain was designed first and foremost as an online co-operative multiplayer game. Now while it works really well online when you and three buddies are taking down enemy AI and attempting to achieve team objectives, using the same method in the single-player game just doesn't really gel and definitely makes things less enjoyable than they had the potential to be. The use of respawning enemies in the single-player game also ends up just coming across as a bit of a cheap alternative to implementing something more intelligent.

Having said all that there are some really enjoyable features in the game. Agent customisation as already mentioned is one but the sheer volume of weaponry included in The Omega Strain is one of the best. While you start with just a basic pistol and stun baton (unless you very wisely went through the training level and grabbed the autos) you'll soon be picking up and using weapons from any enemies you dispatch. While these are discarded after each level, completing it means you'll have unlocked further items to add to your ever-growing arsenal.

Bit by bit you'll start building this up until you have a nice little collection of arms going on. Your performance also contributes towards achieving awards and promotions which in turn will unlock further weapons. You're then faced with deciding what the best kit-out will be to go into each mission with and it's quite satisfying mixing up your weaponry to best effect. There's over 100 lethal weapons in The Omega Strain covering everything from stun batons and pistols through to heavy machine guns and rocket launchers. It's a staggering and impressive array and it's obvious a lot of effort went into creating and reproducing everything on offer here.

The control system in The Omega Strain is probably the most debatable aspect of the game. Syphon Filterers from way back will be right at home once they reacquaint themselves with the wiggly-bum shoulder-button strafing style that's been used here once again. While it's essentially the same system as used in the original Syphon Filter games that we loved so much it did take us a short while to get used to after the few years we've now been playing with the standard thumbstick strafe/move/look set-up adopted by the majority of shooters these days. Just give it a chance though because while at first it might not feel quite like what you're used to it soons grows on you.

What we really liked about the controls was the aiming and targetting system. While The Omega Strain employs an auto-aim feature it's used quite intelligently. Pressing in R1 will result in a target lock-on but your normally red reticule will then change through yellow to green signalling the best time to open fire. In a game where it's important to conserve ammo this means that you can squeeze the trigger only when you'll reap maximum benefit from your shots. The great bit is that the time it takes for your reticule to change colour varies between light and heavy weapons giving a more realistic sense of handling. Also while auto-targetting you can still freely move around and even perform rolls as you strafe around your target.

The other targetting feature is the zoom mode which is activated by pressing in L1. With unscoped weapons this just zooms in slightly whereas scoped weapons produce the more common sniper view. Also due to your need to conserve ammo you'll want to try and pull off as many headshots as possible (remember those from the original Syphon Filter?) and it's our pleasure to report that the zoom mode has really been tightened up since the earlier games making it even more of a joy to use. Once you master the two targetting methods you'll soon find yourself using an enjoyable combination of both as you move around the maps ducking and leaning in some places and strafing and rolling in others while taking out all your foes.

A pity then that generally the AI here is pretty average and quickly becomes predictable with their rather straightforward evasion tactics. It's not really bad but just not very advanced by today's standards. Couple this with the fact that the earlier-mentioned respawning technique is used to populate the maps with a relentless horde of enemies throughout and the overall effect just doesn't satisfy in quite the way it could have. The most cynical of critics might even say that The Omega Strain just hasn't really moved that far from its original PlayStation roots.

Which leads us onto the graphics on offer. The PSX comparison can probably most be drawn on the cutscenes at the beginning of the game and in between the levels. While there's a certain amount of detail evident they just look very dated and clunky especially when compared to the latest standard on show in games like Onimusha 3. Characters in-game are fairly detailed but some of the animations also hark back to the old titles despite being a bit more fluid now on the PS2. Again they're not awful but just far from cutting edge.

The levels in The Omega Strain are mainly large, expansive but really only moderately detailed maps that seamlessly allow the player to move between free-roaming outdoor locales and indoor areas such as buildings. Textures are generally quite good throughout and there's a good variety of locations each offering very different colourful environments. These range from urban inner-city North America to the snow-covered hills of Belarus to a sprawling ancient city and market in Yemen to name just a few.

Visual treats such as shattering glass, muzzle flash, bomb explosions and exploding chunks of plaster and other debris all look quite excellent and show off some very good particle effects. The most enjoyable product of the particle and lighting effects engine would have to be the little carry-over showpiece from earlier Syphon Filter games - the ability to fire your air taser into enemies and hold the trigger in until they burst into flames. Toasted terrorist, anyone?

Sound is a strong point in The Omega Strain. Sound effects for all the weapons, explosions and even footfall as you and the other characters move around are excellent. Voice acting is typically a little over-the-top but also pretty solid and the industrial techno soundtrack is perfect for the genre and for creating the right atmosphere and tension.

We weren't able to play Syphon Filter online for this review (see later) but we can tell you from the wider communiy's experience that where the single-player game suffers the online game excels. That is, it's perfectly balanced as a four-player team co-op multiplayer game and was designed from the ground up with this as its main focus.

You'll notice when playing through certain segments of the single-player game that the odds just seem almost impossibly stacked against you and a bit of help would've gone down really well to keep things moving along. It's in these areas where co-operation in the multiplayer game create a much more balanced and natural flow to the gameplay and they show up quite clearly the glaring single-player faults.

It must be noted that we did try to LAN the game during reviewing to test the multiplayer mode but had no success. We could find no LAN option despite its mention in promotional material, which in our opinion is a huge failing considering the network code is already implemented.

Overall then Syphon Filter: The Omega Strain is far from perfect and not quite the evolution longtime Syphon Filter fans would have hoped for. With its 17 large levels (nine of which can be played online), depth of usable unlockable material and considerable challenge though there's a lot of gameplay here and still quite a bit of fun to be had with the huge arsenal of weaponry if you can be bothered sticking it out to the end.

The character customisation feature is a very welcome addition too and any changes you make can be seen by other players online which we reckon is pretty nifty. It also provides an opportunity for you to show off how much of the game you've unlocked to your teammates as you progressively dress up your in-game character with items as you find them.