Aqua Driller

The first thing you should know about Aqua Driller is that it's free, so already Southend is scoring hit points on Pocket Gamer's Bargain-O-Meter. And the attractive price tag (or lack of one) apparently hasn't prevented the developer from putting as much, if not more effort into the game than a lot of commercial titles out there manage to do. This isn't just a free game, it's an awesome free game.

Because there's no real need to quantify every penny spent, getting into the gameplay is impressively quick. No long menus or screens full of micro-text about licences, publication rights and copyright nonsense.

Perhaps this is just a personal preference, but a game that gets on with the action always seems to be far more enjoyable than one that saps all momentum with set-ups, customisations and blatant adverts before the damn thing actually gets going. Aqua Driller is as concise as they come, and is richer for it.

Working as a submersible miner, it's your job to plough the depths of the ocean to recover valuable minerals. Piloting your small submarine with massive, breast-esque drills mounted on the front is a simple task, and driving it into the sea bed automatically activates the mining equipment.

If it's mineral ore you're drilling into, that particular material is added to your cargo stock for sale once you get back to the surface; otherwise you simply carve yourself a path through the sea bed. This simple mechanic forms the crux of Aqua Driller's entertaining gameplay, and isn't quite as sedate as it might sound.

There are two main factors determining your ability to plunder Davey Jones's Locker; oxygen and hull integrity. Your oxygen tanks steadily deplete throughout your submersion, and only by returning to the crab-like transporter ship on the surface can you replenish your air.

Hull integrity is affected by the amount of drilling and depth of the sub – the small craft can only take so much pressure before it collapses. Naturally you're continuously tempted to push the limitations to their maximum thresholds, and more often than not you'll be caught out on the race back to the surface with that one extra load or crushed to death after visiting Old Hob for a little too long.

Progression through the game depends entirely on upgrading the Aqua Driller vessel so you can forage longer and deeper into the ocean. Each type of ore carries a specific value, with copper and iron at the low end to jade and platinum at the top of the scale.

By increasing the capacity of the oxygen tanks and storage bays, while also ramping up the engine (for increased movement and drilling speeds) and hull (allowing you to take higher pressures and drilling times) your ship can sustain far more oppressive environments for a lot longer – and allow you to bring back that precious cargo.

There's also an interesting storyline running in the background that begins when you find the first in a series of mysterious, buried robots at the bottom of the bedrock. The professor who runs the missions from the transport ship deciphers the locations of other drill sites throughout the world's oceans from these robots memories, and it becomes your secondary duty to find each of these items across the different regions.

The solidity of the bedrock in each region determines when your ship is high enough level to start drilling, so progression through the game is very organic and entirely up to you as to where you go next.

There are some shortcomings in this otherwise delightful game, such as poor audio and an annoying use of the handset's vibrate function (which did my battery no favours at all), but these are easily forgiven.

It's hard to criticise any game that offers such absorbing and lightly entertaining gameplay for free, so all that's left to offer is a hearty recommendation. If you don't like it, there's nothing lost, but I defy any pocket gamer to give Aqua Driller a go and not find themselves addicted to the amusing aquatic antics.