Immediacy is something of a double-edged sword in gaming. Yes, it's great when you can understand and practically master a game in approximately three seconds, but sometimes it's good to have a little more depth.

And that's certainly what you get with Caves n' Chasms, a game about digging into the bowels of the Earth. Depth! Get it? Man, tough audience.

So a grumpy spirit in the shape of a floating green head has trapped you underground, and has decided to get you drilling about to find buried treasures. Only underground is home to things that like tearing your guts out, and your drill only has a limited amount of power.

Additionally, the caverns you explore have blocks stacked in a suspiciously puzzle-like manner. That's probably because this is a puzzle game.

Driller killer

Yep, rather than the free-flowing, noodly Deep Loot or manic, endless, magnificent Doug dug., Caves n' Chasms is a more thoughtful affair. At the start of each stage, you get tasks. You then drill about in the gloom, attempting to find amulets, kill the odd goblin, and make it to the exit before your drill chokes.

Initially, it's this set-up that robs the game of immediacy. It's slow compared to the aforementioned titles, and when you get stuck in a ditch yet again and are forced to restart, the game perches right on the edge of annoying.

But stick with it and everything will start to click. You'll discover how cunning some of the layouts and puzzles are, find yourself determined to beat them, and then enjoy new items and power-ups as they're revealed.

The game will still annoy you fairly frequently - the controls, zooming, and gloom can sometimes combine to leave you stranded one block from safety, your drill conking out at the most inopportune moment.

But that just becomes another reason to tackle the puzzle again, and to do it better next time. Or to take out your frustrations on one of the stupid grinning goblins by drilling its face in.