Metro: Last Light's hardcore 'Ranger Mode' difficulty setting "provides the definitive Metro experience," according to publisher THQ's creative strategist Huw Beynon. Yet it won't be included in the base game, oh no, rather you'll need to pre-order or buy it early to ensure you get a 'Limited Edition' copy. How awfully creative. Presumably it'll be sold separately as DLC too.

Initial release copies of Last Light are upgraded for free to the Limited Edition, which packs a bonus modified AKS-74U rifle and extra military grade bullets to spend, along with Ranger Mode. You don't need to pre-order to receive the LE, but THQ would like you to, just to be safe, and to give it a bit of cash right now.

Ranger Mode in Metro 2033 boosted damaged massively to both you and enemies, made ammo scarcer, and turned the HUD off entirely on the highest difficulty.

While the idea of splitting Last Light's so-called "definitive" mode off into DLC makes one grind one's teeth, it's not the first time. Ranger Mode was technically DLC in Metro 2033 too, though you may not have noticed as you probably played on PC, where it was free and simply patched in. The Xbox 360 edition, however, cost $3.

Oh, and, er, if you fancy pre-ordering Last Light digitally on PS3, which you can from December 18, you'll get a free copy of Homefront. Not very tempting, is it?

Metro: Last Light comes to PC, Xbox 360 and PlayStation 3 in March, THQ confirmed today. Here, check out our E3 preview and this week's new gameplay trailer: