Dive, dive!' 'Fire torpedoes!' 'All ahead... plank?' These are snippets of naval terminology, one of them quite possibly misheard, that we've had rattling around our head since we got into Nintendo's hugely repetitive, strangely addictive, submarine simulator.
Steel Diver reminds us of a modern version of the ancient Lunar Lander genre of games. You have to pilot an incredibly unwieldy vehicle, using a fiddly set of controls to coax it through narrow gaps and twisty caverns, against the clock.
Apart from a bonus round where you can launch torpedoes with the A button, there are no physical controls at all - everything is handled via virtual dials and knobs on the touch screen.
A vertical slider governs your sub's rate of ascent/descent through the water, while a horizontal one makes it chug forwards or backwards at the desired rate, from full reverse thrust to all ahead plank
A twisty dial controls the pitch of the sub, so you can angle it slightly up or down, and separate buttons activate the torpedo tubes. Finally, there's a button to mask the sub in a shroud of bubbles, making it invisible to the enemy's homing torpedoes.
IF DAS BOOT FITS...
It works better than it sounds, but there were many times (like, about every 30 seconds) when it made us wish the 3DS's lower screen was multi-touch. For example, you're descending down a steeply inclined gorge when you see a giant boulder blocking the way ahead.
You whack the engine into reverse to slow the sub's forward momentum, but while you're wrestling with the slider you realise you're still descending, and then - crunch! - you bang into the sea bed.
Being restricted to one control at a time, when there's always at least two that need regular adjustment, is the number one cause of crashing into things. There's a scene in the fourth level when you reach a cavern just littered with the broken remains of failed subs, and we totally felt for those poor souls. It probably wasn't their fault.
The aim is to get to the end of the level as quickly as possible, and you have a choice of three types of sub to do it in. The standard all-rounder is flanked by a smaller, more agile sub and a giant one that packs extra torpedoes. The small sub comes with a vertically firing torpedo (which makes the fifth level boss very easy) and doesn't have a pitch control, so it's definitely the easiest to use - but you'll need to clear each level with all three types.
Enemy subs lie in wait, firing from fixed positions, and ships bombard you with depth charges. You can sometimes return to the surface to recharge your shields, but there's a good chance you'll come under an aerial attack, so the smartest idea is to avoid conflict - another reason why the small sub is our weapon of choice.
SILENT BUT DEADLY
After completing a level you get a 30-second bonus round on the periscope, shooting at enemy ships or subs in a motion controlled minigame - move the 3DS through 360 to see what's on the horizon around you.
Each vessel you sink awards a random decal, which counts towards a special ability such as faster damage recovery, more health, better torpedoes and so on. There are loads to collect, and you need to have multiple copies of the same type before you can activate them.
One of the special powers reveals enemies on the map, but the decal is quite rare and you need five of them. We only ever saw it once, and in the unlikely event we ever get the other four it'll be pointless because we'll know the levels off by heart anyway.