During the fight inside Unicron, Galvatron attempts to choke Hot Rod to death. He attempts to CHOKE. A ROBOT. TO DEATH. IN SPACE. The real mind-bending part? It was working.
More likely, he was trying to make Hot Rod's head pop off like a zit. The part that makes it fridge logic in and of itself is that we've seen that at least in one case, losing your head doesn't kill a Transformer, as Optimus Prime's entire BODY was taken apart in a season 2 episode and he was still very much alive.
And the fridge logic for that, is the question "how the hell did the Decepticons take him apart and yet never find the Matrix during that episode?" Simple, the idea hadn't been concieved of yet.
The comics did show Megatron choking Brawl until the latter's head cracked open from the pressure, disabling him (though not killing him, since he showed up with the rest of the Combaticons a few issues later). Presumably, something like this would've happened to Hot Rod had he not grabbed the Matrix in time.
During Starscream's coronation, the Constructicons serenade him with trumpets. They're robots, who don't breathe, playing instruments you have to blow into. Oh, and the Constructicons? Half of them don't even have mouths!
The trumpets could have built-in dynamics.
In the middle of the Battle of Autobot City, Springer and Arcee try to set up a large cannon. Said large cannon is too heavy for two Transformers to move, wasn't ready to fire, and wasn't even pointed out the window it fires out of. The lesson? Autobots are idiots.
Ultra-Magnus was literally blown apart and then put back together in a few minutes, good as new. Optimus Prime was shot and slashed several times, and he died. Were the Junktikons that good at robot surgery, or did the Autobot suck that much? And it is implied that yes, the Junkions are that good.
Ultra Magnus was blown apart but his parts were still largely intact. Prime's damage was all to the torso, which likely contains whatever passes for a Cybertronian's vital parts.
Wouldn't a planet made up entirely of accumulated junk be the equivalent of a planet made of amputated limbs and guts to a bunch of Transformers? Likewise, wouldn't the Junkions be regarded as a race of Frankenstein monsters?
Not really. If it didn't come from a Transformer, then it's just a piece of junk. Transformers have tools that are separate from themselves. They would be no more uncomfortable with that than a human would be in a junkyard full of broken wooden (read, organic) furniture.
No Optimus Prime on the movie poster? That's because he gets killed relatively early on... Which leads to Fridge Horror when you realize that the poster was teasing kids of the death of their idol before anyone had a clue.
Why does Megatron specifically say "such heroic nonsense!" with an almost pitying tone when Ironhide tries to grab at his foot? Because it is literally heroic, and literally nonsensical, for Ironhide to try and fight him at that point. Ironhide is alone, severely damaged, and surrounded by a dozen heavily armed Decepticons who don't realise he's functional and have just told him their battle plan. His best rational course of action would be to play possum until he has a chance to relay his information to Autobot City... or at least wait until no one's looking to engage the self-destruct or something similar. Megatron realises this immediately and makes that offhand comment, almost to himself, as he puts Ironhide out of his misery. Galvatron or any other version of Megatron would likely have said something like "you fool" or "you still want to fight?" or something similar. This is because G1's Megatron does appreciate acts of heroism, and would consider it worthy to continue to fight against doomed odds; but because he's also Genre Savvy and more than a tactical and strategic match for Prime, he realises Ironhide's just being an idiot at that point. It's actually a very subtle piece of characterisation which no one but a big fan of the series would have appreciated.
When we see the Acid Pool, Spike's dad and company is about to be dipped. They were on the last moon Unicron ate, and if the transformers were dropped chronologically (nothing says otherwise), then that means that everybody on the first moon and the planet from the opening scene who wasn't crushed to death, met their fate in the pool.
Actually, Bumblebee was seen with spike, and Jazz and Cliffjumper can be seen first just behind them in the line of doom, and then standing on the acid pit cover at the end. Unicron apparently eats in something other than chronological order, and all the people on the moons lived.
On a side not related to the acid pit; We see a long line of bodies being carried to be dropped in. and they were falling pretty frequently. Firstly there's the shear horror of the fact that every second Daniel took to blast that cover another fell to their agonizing death, and then there's the question of where all the ones after the autobots in the line went.
One Possibility is that the conveyor got shot up and stopped working as well, although this leads to more horror, since the victims were therefore trapped hanging from the ceiling until Unicron went up and took them with him.
It would be strange if the freed autobots didn't free those who were hanging.