Sledgehammer (aka Gear Grinder) is one of those weird games that can only come out of Russia... in a parallel future, where trucks can transform from jet-engined superracer into an armored and heavily armed beast, and police are packed with gatling guns and more and enforce laws with lethal force, you have been executed for slaughtering innocents with your truck, but you woke up mysteriously next to a shiny new transforming truck... and was told to get through some training so you can undergo some missions for this mysterious benefactor...
Basically you drive around like some weird vigilante who needs to cause maximum destruction. You have front bumper spikes, side spinning saws (later), front firing weapons (primary and secondary), and rear mine dispensers. Your truck can also be upgraded with better armor, transmission, engine, and so on.
The fighting is about what you'd expect in such a game... You are in 3rd person but very low, so your truck will obstruct your view ahead. Fortunately you can pretty much run through almost anything in your way, or your shoot your way through. There are missions that are pure racing (where you use racing mode, complete with afterburning engines) pure combat (survive arena for X seconds), or run-n-gun (fight enemies as you try to make it through checkpoints). The more you kill the more time on the clock you get, but the the more damage you suffer. There are a few oddball missions such as "pilot a RC bomb drone" or "max speed into a cafe".
The problem is the first level's "end mission". Instead of a boss fight, you're basically put into a gauntlet that's basically 3 missions together. First is a checkpoint race where you need to pass through little tokens to get extra time. When you reach a mall you crash through to land and found the way's blocked, and you need to kill X police cars to get out. Then it's a long run-n-gun to the final endpoint... where I've tried about 10 times, with max upgrades, and I keep running out of time (the only way to gain time is kill the cops, and they sometimes aren't fast enough so you can't kill them (or I'm taking too many go-fast upgrades?!) So I can't even get onto "level 2" (i.e. next city).
Voiceover is atrocious, storyline is outrageous, sound is... mediocre. Graphics are tolerable. This is a weird game. If you like your idea of wanton destruction, give it a try. But not quite my cup of tea.