About the ranking system:
Like all Platinum games, and most hack and slash'a in general, this game has a grading system. The grades range from D/C/B/A/S, with SS being the highest rank achieved.
The grades are, in a word, "arbitrary".
First off, if you're aiming for no damage/speed, the most you can earn is a 400 points. 200 for avoiding damage, and 200 for a fast clear.
This is usually good enough for an S on low difficulties, but only nets an A or B at higher levels.
Basic combo attacks net you no points. That big sledgehammer you one shot killed everyone with in 10 seconds? Congratulations you earned no extra points.
Instead, you get points for the finisher "transformation attack", triggerer upon completion of a combo string. I'm not sure about the values, but they list the points accumulated after an encounter, and they're usually something like +40 points added to the total score, so it can't be a high number. Maybe 5 to 10 points each.
You also earn points for reversals, counters, parry's, "focus mode" (Bullet time, triggered on dodge), headshots.. Nearly anything BUT just killing things with basics.
This means heavy hitters like Grimlock usually rank poorly, because he kills things too quick. Literally EVERY option kills in one or two hits, and often takes out entire groups.
On the other hand, Bumblebee racks up SS grades without even trying, because he does very little damage, yet his combo string attacks result in two vehical attacks at a time, and he can combo off the weakest enemy for a long time.
So yeah, arbitrary.
Personally, I don't like having to find loopholes in a combat system to score big. With Grimlock, you're gonna have to farm points by whatever means you can, if you care about playing the scoring game. It's boring grinding, and defeats the purpose of playing.
That said, the games still a lot of fun to play, and the ranking system is just one aspect of the game. It's unbelievably fun to send Grimlock in with a big hammer or glove weapons, and walk all over everyone.
Also, I'd imagine heavy hitters score better on harder settings, which could be a "feature" and not a flaw. Different characters for different settings.
