It was never going to take long was it? The Worms franchise has appeared on every gaming system ever created (almost), and the simple turn-based action series seems perfectly suited to the PSP. Lovely 2D visuals, simple controls, multiplayer gaming, game share and online play... Oh, the features that would have made Worms: Open Warfare on the PSP a must have, haven't been included - oops!

To be fair, the lovely 2D visuals and the simple controls are here, and are about as great as you'd expect from the PSP. Worms has always been best in its 2D style, and it's nice to play a modern version that doesn't attempt to cram the simple gameplay into a much more complex and sprawling 3D world. This is classic Worms gameplay, brought to life rather well on the PSP's ideal widescreen display, with sharp, colourful visuals.

If you've never played Worms before, there really isn't much to it. You take control of a team of worms who must destroy other teams of worms. In the case of Worms: Open Warfare, up to four teams can be on the battlefield at once. It's a turn-based game, so you are given control of a member of your team and have a set time limit to carry out your move. You are free to move your worm around the level during this time, but can only carry out one command - two on occasion. Whether this is firing a bazooka at an enemy worm, or simply teleporting to a new area on the level, that's it - your turn is over.

All players take turns, taking control of one worm at a time, until there is a victor. Health pick-ups and special items are dropped from the sky, but you often have to consider if you've got time to get to a pick-up and still carry out an attack or if a health pick-up is really worth it if you're going to be sitting in the open for a few turns. With the variety of weapons on offer, there aren't many locations that are totally safe (although the randomly generated levels do promote hiding sometimes), but sitting in the open is asking for a homing missile to be fired at your face.

Long-time worms fans will appreciate that some old favourites, such as the exploding sheep, have been included, and newcomers will take to the gameplay extremely quickly. All weapons are handled in much the same way, with a target showing where you are aiming. Close-quarters weapons, such as the Uzi, are simply aimed and fired, but long-range weapons need a little more skill. A power meter shows how far you want to fire your selected weapon, and this must be judged along with the wind direction and speed, making precise long-range attacks a key weapon in the experienced player's arsenal.

Sadly, despite the hugely enjoyable gameplay, the game modes are severely lacking. As a lone player you're limited to straightforward games against the CPU and Challenges against progressively more difficult CPU AI. While recent Worms titles have dabbled with a story mode with mixed success, the absence of one here makes the whole package feel a little empty.

Why wasn't online play included?

Multiplayer is really where you'll get the most out of the game, but even this is severely limited. You can play with up to three friends over a local wireless connection or by using a single PSP and passing the handheld around, but this seriously limits the game's multiplayer potential. Where's the game sharing functionality and the online play? Two features that would have made this a must own multiplayer PSP title. You can name the members of your own team and tweak game options to make battles a little different to the norm, but the multiplayer is so restricted without online play.

Worms: Open Warfare plays great and is one of the best worms titles to appear in some time, but as a complete game it's lacking in key areas. Without a single-player mode to really sink your teeth into and the multiplayer mode being limited to local play only, it's hard to see anyone other than complete Worms nuts getting much from the game. The Worms' first outing on the PSP plays well, but rather strangely doesn't pack a big enough punch.