We'll start with the driving. The vehicles often have squirrely handling, you can't switch from a robot to a car while in midair, and a tree sloth could climb buildings faster than you - handicaps that add up to tranquilize what could have been amazingly fluid and absolutely genre-destroying one-of-a-kind chase sequences.
Also, while pursuing a fleeing target as nitro-powered semi truck Optimus Prime, with buses, tanks, and entire stone archways (sorry, fancy hotel) literally bouncing right off us, we came to a foot-tall concrete pedestal that used to have a flowerpot on it - and came smashing to a dead stop. Same thing happened with a barely two foot-tall brick retaining wall around a parking lot. We literally had to transform back into a zillion foot-tall robot and jump - not walk - over it.
Luckily, the Decepticon campaign has much less of a problem in this area. It's focus on mostly flying and even burrowing transformers - and the less claustrophobic environs they travel - makes navigation a much simpler affair.
But it still has other problems, which leads us to the blowing stuff up bit. Your target lock can't remember what "lock" means, but it almost doesn't matter. Why? Because, even though every single transformer has bullet-spraying space-artillery, every non-grunt enemy has a force field that renders him immune to gunfire, even in vehicle mode. You do have a basic, three or four-punch combo that you'll find yourself tediously hammering out ad nauseum, but it too will be ineffective 90% of the time because these bums block so constantly, they should transform into turtles instead of vehicles.
Luckily, thrown objects like cars, trees, and chain link fences can inexplicably tear right through an opponent's guard. So your skyscraper-perforating guns and metal-shearing punches may prove useless, but your enemy has no defense against the unstoppable power of an elm sapling you've pulled up and flicked in his direction. True, even heavy projectiles like cars rarely do more than nick your foe's health bar, but they can stun him and give you a chance to squeeze in a punch or two before he resumes his invulnerable cower behind crossed forearms again. It's also tough to aim when throwing, a handicap we didn't realize until we played the Wii version, with its more strafe-friendly, far more precise controls. So much for those bombastic giant robot battles we were eagerly anticipating.