Hope Bringer: Any Autobot in the middle of a firefight praying to Primus for survival sees their prayer answered when Optimus shows up.
Autobot Soldier: It's Optimus Prime! The 'Cons are in for it now!
Hurting Hero: No other incarnation of the character has come to this level. It pains Optimus to see so many casualties mounting on his side. Still doesn't stop him from being monumentally Badass and never losing hope.
One particular moment in the game shows this most clearly: Optimus comes to a control room and finds all the Autobots inside were massacred by Starscream.
I Did What I Hadto Do: He didn't like the decision to retreat and admits that he was tempted to fight to the end, but as Cybertron is longer able to support life and the Decepticons are winning the war, he saw no other option
Ramming Always Works: In his vehicle mode, he can destroy enemies by ramming them and uses this as an attack when fought as Megatron in the final battle.
Reasonable Authority Figure: Optimus had every right to be mad at Grimlock for leaving his post and opening the Ark to Decepticon assualt, but he instead felt that Grimlock must've had a good reason for doing so and it turns out he did, so Optimus sends Jazz and Cliffjumper to find him and his team.
A powerful, very large, Autobot who leads a group known as the Lightning Strike Coalition Force. He was captured by Shockwave and his Insecticons and was made even more powerful. His Special Ability is Dino Mode. He dislikes Optimus' less aggressive attitude toward the Decepticons and displays violent behavior that indicates he's not in the best mental health, but is ultimately a good guy underneath it all. He consciously remembers Shockwave rebuilding him and can grasp that power was siphoned away from his brain's circuitry. After Starscream somewhat inadvertently frees him, he plans to get his revenge after rescuing his team. Voiced by Gregg Berger.
Ax-Crazy / Blood Knight: It's somewhat ambigous if he's one or the other, or both. He's more violent than the Autobots, and most of the Decepticons for that matter. He clearly enjoys killing Decepticons and his locker in his room is full of the severed heads of 'Cons that he's killed.
The Big Guy: Literally, most transformers in the game at best come up to his knee. In his dino-mode, only Bruticus and Metroplex are bigger than him.
Bully Hunter: According to his character profile on the box of his official Voyager-Class Fall of Cybertron Toy, (released Late December 2012) Grimlock's motivation for his loyalty to Optimus Prime is listed as thus:
"He is smart enough to recognize a bully when he sees one; and Grimlock does not like bullies."
Grievous Harm with a Body: His main projectile in robot mode has him pick up enemies and throw them (except Bruiser and Leapers, they're too big), which instantly kills them and most anything they hit. Using this with groups of enemies can let him kill dozens at a time.
Informed Flaw: Grimlock's supposedly stupid due to energy be siphoned from his brain's functions, but apart from him commenting about having difficulty thinking and having a hard time saying "experiments", he doesn't appear to be unintelligent.
Jerk with a Heart of Gold: Sure, he doesn't get along very well with his fellow Autobots (particularly Optimus Prime), but he's shown to care a lot for his team.
He also at least agrees with Optimus when it comes to stopping Megatron from plundering another planet and protecting the innocent.
Mighty Glacier: He's slower and a bigger target than a normal character, but has five times as much health and can block projectiles with his shield, so that's not a huge issue, plus he's still faster than most enemies he comes across. His melee attacks kill most enemies in one hit and he can instant kill everything but Leapers and Insecticon Bruisers using executions, which also restores his health, or by throwing them. That's without going into his T-rex mode.
Nice Job Breaking It, Hero: Assuming the player uses Optimus in the last fight the portal destabilizing from Grimlock breaking the space bridge controls interrupting the fight will save Megatron as Optimus is about to kill him, though alternatively, if the player used Megatron, the event will save Optimus.
Now That's Using Your Teeth: He turns into a T-rex, so it should be obvious. Apart from the bite attack that's part of his combo move, his executions on Insecticons in dino-form, even bruisers, consists of biting clean through them.
One-Man Army: Has the largest number of enemies in his levels of any character and his levels include walking right into the heart of the insecticon's main hive and killing every one of them that tries fighting him.
Impaled with Extreme Prejudice: How he sets for executions in robot mode, and on smaller decepticons he repeatedly stabs them after doing so. If he does it to an Insecticon swarmer, he tears them off his sword.
Kill It with Fire: With a leaper, which he can only do in dino mode, has him toss the into air and impale them on the tip of his tail and roast them with his Breath Weapon.
Papa Wolf: Anyone who hurts his team learns this the hard way.
Revenge Before Reason: While not played straight since he does put rescuing his team before getting revenge, when he gets his chance and nearly kills Shockwave before proceeding to destroy the space bridge, the bridge explodes before he can escape.
Super Mode: His Special Ability. He transforms into a Tyrannosaurus rex, trading in his sword and shield for stomp attacks, bites and tail sweeps. These have greater reach and allow him to make short work of huge crowds of enemies. He can also execute Leapers (and can destroy without have to hit their unarmored back unlike in robot mode) and Bruisers in this form and gains a powerful flamethrower attack, which while not as powerful as hie melee attacks, does send enemies running scared when used meaning he can chase them down and finish them off without resistance. When he dashes, he'll also knock any enemies aside no matter how big they are.
Lightning Bruiser: Very fast alt-mode despite being the largest character in the game apart from Grimlock, Bruticus and Metroplex.
Ramming Always Works: For him it does, seeing as his alt-mode is a Triceratops. Shockwave's logs even state that it was the intent of his design.
Size Shifter: Slug's robot mode is around the size of Bumblebee and Jazz, but his alt-mode is the size of an Insecticon bruiser (this makes him the fourth largest character in the game next Grimlock in Dino-form, Bruticus, and Metroplex). If you look at him after he transforms, you'll notice that he grows bigger.
When All You Have Is Ramming: He doesn't seem to have any weapons and all the fighting he does onscreen is in his dino-form by ramming everything in his path. This works against all of his foes and he even appears to be able to tunnel with it.
An expert bomber and good friend of Grimlock. His modifications cause him to become a Pterodactyl. Voiced by Mark Allan Stewart.
Keet: Has a surprisingly upbeat attitude despite the current situation and actually considers the changes done to him an improvement, liking the new power he has. Granted, he wasn't conscious like Grimlock was when Shockwave rebuilt him and he didn't have any changes done to his mind.
Lightning Bruiser: A Fragile Speedster compared to the other Dinobots (he's based on a fragile flying creature rather than a stocky muscular one), but his speed and firepower makes him a lethal foe. He's also strong enough to carry Grimlock in robot mode.
Strong as They Need to Be: His strength tends to also increase when he uses his Grappling Hook. When not using it, he needed Cliffjumper to help him move a fairly large chunk of debris. When using it, he could easily yank Bruticus' leg out from under him.
Spanner in the Works: The Autobots didn't even know he existed until power was re-routed to a set of artillery cannons that were part of his alt-mode.
Story Breaker Power: His sudden appearance basically motivates everything in the plot. He singlehandedly stops any and all attempts to assault the Ark again, gives Megatron a beating which makes Starscream the new leader and prompting Soundwave to rebuild him a new body, the Energon given to him means that the Autobots need to find other reserves and with the Ark a no-go, Megatron is forced to find Trypticon.
There Is No Kill Like Over Kill: Almost all of his attacks, be it blasting 'Cons with his giant cannons bigger than they are, or crushing them. And let's not forget the beatdown he gave Megatron.
Impaled with Extreme Prejudice: When playing as Megatron for the final fight, Optimus disarms and impales him with his own sword. Megatron takes it well, as he uses this opportunity to grab Optimus and land some blows.
The Juggernaut: Megatron's main gameplay mechanic is that he is incredibly mobile and signature weapon is horrifically powerful.
Autobot Soldier: That's a hit, I think we hurt him!
Autobot General: You didn't even hurt his feelings!
Kick the Dog: Besides trying to kill the Autobots when all they're trying to do is escape the war, he also kills two captured Autobots right in front of Optimus just to spite him.
Kill 'em All: What he wants to do to the Autobots. As he puts it: "I'll stop when all of you are dead!"
Mook Horror Show: All throughout his chapter, you get to hear the panicked transmissions of Autobots who are stuck in the middle of Megatron's path as he cuts a swathe through their base. Single-handedly.
Tautological Templar: Argues that everything he does is for the good of Cybertron and sees anybody that opposes him as being in the wrong. His plan to convert Trypticon into the Nemesis was in his mind an act of compassion since it would allow him to make up for his earlier defeat, even though it would leave him stuck in that form.
Wrath: His desire to kill Optimus and the Autobots is heavily motivated by personal hate.
Megatron's treacherous second-in-command. His Special Ability is Cloak. Voiced by Sam Riegel.
0% Approval Rating: By the end of the game. Not only seen as an enemy by the Autobots, but the only Decepticons that might have had any faith in him as a leader were either killed by Megatron or abandoned him when they saw how much of a coward he was.
Even Teletraan I doesn't like him, as one of it's "Goodbye" phrases to the Combaticons is "You are unlikely to survive Starscream's leadership."
Nice Job Fixing It, Villain: He let Grimlock escape, putting a stop to Shockwave's plans to use him and the Dinobots as weapons. Not only did the run over a big chunk of the surviving Decepticons, but given what the audio logs found early the game said about the Ark's light armament, allowing Grimlock to go free and destroy the Space Bridge might have likely saved the Ark as well.
Spanner in the Works: After being kicked out of the Decepticon army by the recently restored Megatron, he decides to become one of these in order to give Megatron the proverbial middle finger by interfering with Shockwave's experiments, which culminates with him inadvertantly setting the captive Dinobots free.
Awesome, but Impractical: Bruticus' standard melee attacks. They're instant kills, more appealing to look at than his Shield Bash, but are also slow and awkward to aim that it's hard to even hit a stationary target with them.
Benevolent Boss: Onslaught, to an extent. He berates his men, though some of that might just be him in a bad mood due to putting up with Starscream, but he never needlessly sacrifices or abuses them, and is overall pretty fair to themnote When they take the Energon Transport, Onslaught says "my team" salvaged the mission, not just himself.
Glass Cannon: Vortex, he has dual mortars instead of the usual helicopter missiles and their use, along with his really powerful shockwave, means your only problem is getting the bots in your sights before they kill you.
Mighty Glacier: Brawl and Bruticus. The latter takes the trope to an extreme. He's the slowest and largest character in the game, and he can't even boost or jump like Grimlock can, so he's guaranteed to get shot. But he's got ten times the health of a normal character and his shields recharge extremely fast, and the rare moment he is in any danger, he can block any projectiles with his rotor shield (even the BFGs in his levels that are as big as him). For a weapon, he has a flamethrower that kills most anything in one hit (and has unlimited ammo), along with his Sonic Pain Wave, which recharges very quickly so it can be used over and over.
Fragile Speedster: Blast Off, even using the boost as Vortex you won't be able keep up with him.
Cool Plane: Blast Off's alt-mode. Vortex's helicopter alt-mode can also turn into this for a boost in speed.
Death from Above: An attack Bruticus uses when fought as Jazz, which can't be used in the segments where he's playable, has him fire a bunch of shots from the cannons on his back that land on spots all over the area.
Vitriolic Best Buds: A lot of the dialogue between them consists of light jabs, snarks, and cranky calls to hurry it up (though it's justified, as they have a strict time limit for their mission, and putting up with Starscreamprobably doesn't help). However, they function very well as a team.
A Decepticon scientist who exploits science for his own sick deeds. He's responsible for turning Grimlock and his team into the Dinobots. Voiced by Steve Blum.
Arm Cannon: Gained one after Grimlock ripped off his left arm.
Bunny-Ears Lawyer: He's not especially liked by most of the Decepticons, due his experiments scaring the crap out of them, but Megatron isn't bothered and considers him invaluable due to his scientific genius, and is one of the few Decepticons in either game to whom Megatron shows any respect. He apparently trusts him so much that he believed him about the tower Shockwave studied in the Sea of Rust being a valuable find without him even telling him what it was.
Creepy Monotone: His cold, nigh-emotionless voice is matched only by Soundwave's.
Gone Horribly Right: His plans to experiment on the team of captured Autobots and remake them into brutal killing machines who would be loyal to the Decepticons. The first part worked wonderfully, resulting in the creation of the Dinobots. The part about switching their faction loyalties to the Decepticon side, not so much, which came back to bite him.
Intrigued By Earth: He is a scientist and finds examining Earth rather interesting, which hints that he hasn't looked at any worlds beyond Cybertron previously since he's surprised to find out that Earth's surface isn't metal.
Surrounded by Idiots: States this in one of his audio logs found in Chapter 4, where he's annoyed with how the rest of the Decepticons are mostly seeing value in a lake of energon while he sees far more value in the space bridge, and is annoyed with how Starscream only views it as an energon refinery.
The Stoic: He puts up with Starscream without losing his cool (note that he's the only Decepticon that's able to do that) and even Grimlock doesn't scare him for the most part; helps that most of the time Shockwave isn't in the same place as Grimlock when speaking to him.
Not So Stoic: He expresses a bit more emotion in his audio logs.
This Cannot Be!: His reaction to Grimlock transforming out of his trap, moments before ripping Shockwave's arm off.
Well-Intentioned Extremist: Implied by some of his audio logs, with him planning to restore Cybertron and Word of God is that his loyalty is to Cybertron itself first and foremost, though outwardly he acts loyal to Megatron.
A group of creatures that emerged from the underbelly of Cybertron and were discovered by Shockwave, who calls them his "pets". Most simply act as mooks and cannon fodder, but the three that display distinct personalities are Sharpshot, Hardshell, and Kickback. They lead the other Insecticons and are appear to only obey Shockwave due to unspecified methods of mind-control. Voiced by Troy Baker (Kickback) and Steve Blum (Sharpshot).
Ax-Crazy: Sharpshot and Kickback, even more so than Megatron. The former tortured Snarl brutally and taunted Grimlock about it, and even the other Decepticons have remarked that he enjoys the "testing process" way too much. One of Shockwave's logs explicitly labels Kickback as a psychopath, and his dialogue leaves nothing to question.
Combat Pragmatist: Hardshell, who when faced with Grimlock, leaps into a huge mech armed with a pair of massive rocket launchers and a shield that keeps Grimlock's melee attacks from hitting it, meaning it can only be damaged by throwing objects at it.
Dirty Coward: Kickback and Sharpshot. Out of Grimlock's reach, they constantly taunt him. Upon finding out that things aren't going their way, Kickback tries to run away and Sharpshot screams at Grimlock to stay away from him.
The Dreaded: In an odd case where it's the guys they're supposed to be on the same side as that are afraid of them. The common Decepticons are terrified of Insecticons and see them as little more than opportunistic killers, and, they're absolutely right. In chapter XII, the Insecticons will attack the Decepticon Mooks as well as Grimlock. Even Shockwave considers Kickback and Sharpshot dangerous.