There's a memorable scene in Raiders of the Lost Ark in which adventurer Indiana Jones finds himself face-to-face with a flamboyant swordsman who twirls his blade in anticipation of a fight.

Before any clash of swords, however, an annoyed Indy pulls out his pistol and shoots the fellow.

Despite all his skill in wielding a blade, the swordsman was ill-equipped for the fight at hand. He may have successfully terrorised countless locals with his scimitar, but he simply wasn't prepared to face a new challenger bearing more sophisticated technology.

Fieldrunners finds itself in a similar position.

Originally released for iPhone back in 2008, and updated many times since, it now faces a sophisticated new challenge with iPad - yet doesn't seem equipped to face it.

So while the quality of gameplay remains consistent with previous versions, there's nothing to distinguish this iPad iteration as being more enjoyable or sharper in terms of taking advantage of the new hardware.

Marching orders

Without any story to speak of, Fieldrunners for iPad goes straight for the action on five maps.

Each offers three modes - Classic, Extended, and Endless - unlocked in succession. Classic runs to 100 waves, giving you a small arsenal of four weapons with which to defend your base. Extended also features 100 waves, though you're granted an additional armaments. Endless obviously acts as an infinite survival mode.

The weapons, which include a basic Gatling turret, missile launcher, decelerating goo tower, and electric Tesla coil, aren't new.

Thankfully, the enemies break out with some originality.

Foot soldiers, half-tracks, biker officers and airships make an aggressive push across the screen. In spite of the limited tower selection, these varied enemies force you to make strategic decisions about your defences.

Aircraft, for example, fly above towers and so can't be herded through a makeshift maze of defences. As such, your towers must be arranged so that you're able to funnel ground units through constructed pathways while also ensuring the right towers can target passing aircraft.

That enemies succumb to attack from specific towers further encourages careful planning.

Dissent among the ranks

Of course, none of this is new - Fieldrunners for iPad offers this same gameplay in the versions available on iPhone, iPod touch and PSP. That there are no new features or content at launch makes this iPad release an unconvincing proposition.

Of course, the prospect of downloadable content in the future is certainly intriguing. Developer Subatomic has promised free updates as well as paid-for DLC, but it does nothing to render the game more attractive right now. Increasing the graphical resolution isn't a compelling enough reason to spend an additional $8 downloading an 18 month-old tower defence game.

In fact, time has only served to highlight some of the game's shortcomings.

Structuring levels in Classic and Extended modes at a minimum of 100 waves, for instance, unnecessarily drags out games. Levels ought to be concentrated into no more than 40-50 waves of good action and not strung out for their own sake.

It's also worth noting high scores are currently local only - although that's because the game's chosen social platform, OpenFeint, doesn't yet support iPad.

All-in all then, if you've never played Fieldrunners before this version would be a mildly amusing package, yet while the original version is available on iPhone for $3, the additional screensize alone hardly lends itself to recommendation.

To that extent, Fieldrunners for iPad is a classic example of a launch game: functional, but not (yet) well enough equipped to be considered a must-have.