You're required to help out other people along the way, too, including a factory worker who'll open security doors in return for your assistance. There's also a young UN troop who you guide across pits of radiation in the dark with your torch. It's all carefully orchestrated and helps pad out a forgettable storyline.
As well as creeping through murky shafts with your flashlight, you've a set of Sam Fisher-style goggles to help you out - but while you've got the standard issue night-vision and infra-red modes, you're also equipped with EDSU filters which can pick out electronic devices that aren't initially visible. This is key when stepping through areas packed with landmines - one quick shot from distance will sort them out.
Above: It's simple to target an enemy, but they'll dive and roll to dodge your bullets
It's good to have these accessories and at one time or another you'll need them, but Dark Mirror lets you attack missions and enemy grunts in a way which suits your style. And because of this, it's fun to play.
You won't find too many original ideas here, but the whole package plays out brilliantly. But just as the ever changing action hits its peak - like battling specially armoured soldiers, or the unexpected tank attack - you're hit by a massive increase in difficulty.