OK, this is a tough one. A smart, artfully-designed, but super-challenging game, that is, that’s guaranteed to keep you on your toes – well, the tips of your fingers, anyway – for hours of fun and frustration.

As its name implies, Mercury Meltdown involves that peculiar, temperamental metal that’s a silvery liquid at room temperatures and therefore immensely fascinating to look at and play with. The object of the game is simply to move quivering, simulated blobs of mercury through a series of obstacle courses of increasing fiendishness. Not only are there various moving gates, sharp corners, and other nasties to contend with, but bits of your blob, or even the whole thing, can easily slide off the edge of the seemingly raised playing surface – in game terms, a loss. But the more metal you manage to pull across the finish line  – and the quicker you get there and the more bonuses you collect on the way – the higher your score in each level.

Moving your mercury is the tough part. It calls for sliding your finger tip across the phone’s touchscreen to drag the blob in a desired direction. But just like the real thing, these simulated blobs display realistic dynamics, including physical momentum: Once they get moving in a certain direction, they tend to keep moving until slowed or pushed a different way – a perfect illustration of Newton’s First Law of Motion. But just to make things more interesting, the surfaces that the mercury moves across can change from ultra-slippery to sticky and slow, all in a matter of millimeters on the screen.

Luckily, if you do lose a blob over the edge, you won’t necessarily lose everything. The game graciously offers a Retry button and, in Tutorial mode, it pops hints and warnings onto the screen to help you on your way.

If you’re feeling particularly self-confident (or suicidal) you can jump ahead to play upper levels without having completed any previous ones. This may mean confronting a variety of obstacles that you’ve not encountered before, however, which can raise a level’s difficulty to an insurmountable level. It’s best, we’d say, to work your way through Mercury Meltdown’s more than 50 levels in order, one by one. Your patience will be rewarded.

Mercury Meltdown was originally released for certain gaming consoles, where it was a big hit. But here it is, ready for your Nokia Symbian smartphone, care of the developers at IG Fun.

At just $1.99 (USD) and only 0.42MB of memory, Mercury Meltdown packs expansive fun into an economical budget. There is also a Lite version of the app that you can try for free in Ovi Store.