Following on from the WiiWare release of its sister title, Pirates: The Key of Dreams, Pirates: Duels on the High Seas for Nintendo DS is a top-down action game that puts you at the helm of a Pirate ship on a voyage for ancient treasure, blasting through fleets of enemies and sea monsters as you go. Oxygen Games granted me the opportunity to go hands-on with a preview build of the game prior to its release in the UK later this month, and after some extended playtime, here are my impressions.

Your single-player quest begins with the selection of a difficulty level corresponding to the size of your ship (the greater the size, the lesser the difficulty). The ship's controls are executed exclusively with buttons; the D-pad steers, while the shoulder buttons propel the vessel either forwards (R) or backwards (L). Weapons are fired using the face buttons, with the port and starboard cannons being activated by A, while consumable pick-up secondary weapons (such as rockets and mines) are triggered using B. With just a little practice, this scheme proves more than adequate for manoeuvring your vessel in between obstacles and around enemies.

Pirates: Duels on the High Seas employs 3D graphics to present the game's action on the upper screen, and the results are quite effective, if rather lacking in appreciable textural and architectural variety across the different environments. I noticed some slowdown affecting a few situations involving a particularly large number of enemy ships on-screen at once, but otherwise the game runs fairly smoothly. On the lower screen, a simple map displays a bird's-eye view of the area around your ship, indicating the presence of enemy vessels or weapon installations with skull icons. These can assist in the formulation of a little advance planning, if necessary.

The sound design on show here is very sparse. Without music to accompany the action during a level, just a few basic weapon fire sound effects and seagull noises are left to carry the audio load. There is some music used in tandem with the brief static story scenes between levels, and a quick fanfare for clearing an area, but otherwise there is nothing to speak of for a soundtrack. What little music is present is thematically suitable, if rather uninspired.

Though the presence of a top-down perspective and a ship capable of picking up various weapons may evoke thoughts of a vertically scrolling shooter, Pirates: Duels on the High Seas is structurally more similar to a side-scrolling fighting game, such as the Subspace Emissary component of Super Smash Bros. Brawl. Typically, you navigate through levels on a linear path, often at liberty to simply bypass enemies rather than face them down. Combat is only necessary when a locked gate prevents you from progressing until, for example, you have destroyed all the ships in that particular area. There can be rewards for destroying enemy ships along your way, such as gold or new crew members that enhance your ship's abilities, but these inducements appear seldom enough to provide scant encouragement to methodically destroy every enemy that crosses your path.

When engaging in combat does become imperative, the intention is clearly for you to manoeuvre your vessel such that it can deliver devastating broadsides to your opponents while evading enemy fire. However, the enemy AI and balance of the game's statistics mean that such dexterity is seldom necessary to progress through the next gate. When dealing with smaller vessels, it is quite safe to remain stationary while pumping out cannon fire until they sink. Also, the collectible sub-weapons can make quick work out of larger ships and cannon placements, but in their absence the process simply becomes something of an exercise in tedium rather than tension.

Fighting the game's biggest enemies, such as a colossal battleship or a sea dragon, can require greater care and attention, but this is mitigated by the inclusion of an ability to continually replenish your ship's health. Selectable from an icon on the touch screen after you find a shipwright to become part of your crew, this option can make your ship near-invulnerable at the cost of a quite trivial amount of gold (which is relatively ubiquitous in itself). Combined with the fact that (most of the time) your ship is in little danger from the standard enemy boats, this low price for such a useful ability makes it all too easy to get out of a tight spot in one of the bigger battles. It also renders the other selectable crew-based ship abilities, such as greater range for your weaponry or a wider field of vision on the lower screen, practically irrelevant due to their comparatively meagre usefulness.

Overall, Pirates: Duels on the High Seas has some quite solid foundations in terms of controls and graphics, but some curious design choices mean that these are not being fully exploited. Also, it remains to be seen whether there is sufficient variety in the tasks and level designs to maintain players' interest throughout the course of the game. In addition to the quite substantial single-player campaign, Pirates: Duels on the High Seas will feature multiplayer modes for up to four people to participate, with or without extra game cards. Unfortunately, these options could not be utilised in this preview build of the game. UK DS owners will have the opportunity to discover how multiplayer Pirate-duelling will shape up, along with the rest of the game, when the final version goes on sale on August 22.