A decade after it's initial release, and Gun Metal is still awesome. For me, this game is a masterclass in focussed design. It doesn't try to be clever, with lots of gimmicks that are only there for their own sake. It just gives you good, solid, arcade-style action, and it does it extremely well. Your mech isn't loaded with three dozen special features that you completely forget about in the heat of the action. It does a limited number of things, but those are the only things you need it to do, and they all feel relevant. Running, strafing, transforming, boosting, barrel-rolling to dodge fire, and all the while firing, firing, firing on the enemy.
Yes, it does betray it's Xbox origins in the slightly awkward mouse control and limited graphics options, but honestly, once you dive in and get blasting, it all feels very natural. The barrel-rolling to dodge in jet mode feels particularly intuitive, as it's on the keys you use for strafing in mech mode (A and D by defaut as you'd expect). And you can always plug a control pad in if you find the mouse control a bit too hazy.
As far as I'm aware there's only one voice in the game, the guy who gives you orders, and he puts in a good performance. Maybe not award-winning, but solid, with simple dialogue, no ridiculous cringe-inducing histrionics, and status updates and encouragements as you progress through each mission. It's nice to actually be told you're doing well instead of being berated for something or other all the time! =P
In closing, if you want some simple, straightforward action with just enough depth to be engaging without being overwhelming, Gun Metal is for you.