Oh, man... So many things. Just off the top of my head
Palpatine brought back with absolutely no reason given beyond ''Sith cloning/Somehow Palpatine returned''
We're somehow expected to believe the Death Star had pieces just laying around on some random planet despite watching the whole FUCKING thing explode in RotJ.
Kylo's ship violently spins out of control, crashes and EXPLODES after he tries to run Rey down with it and he somehow gets out 2 seconds later without a scratch on him.
''They fly now?!'' Meanwhile, we've literally had jetpacks in-universe since way back in the prequel days with Jango Fett.
''I am all the Sith/I am all the Jedi'' was such a shit way to try to copy the MCU. Not to mention it sounds cringe as fuck
Rey and Kylo spend the whole trilogy trying to kill each other and then all of a sudden they kiss because reasons. I guess she really liked him shirtless?
Palpatine is so unbelievably stupid when facing Rey and Kylo. He was previously shown to effortlessly ragdoll them and then all of a sudden he forgets he has a brain and just spams his lightning which is clearly not working and ends up killing himself
Finn's big secret he was gonna tell Rey when he thought they were dying is literally never actually revealed in the movie. You have to go seek an outside interview to know wtf he was gonna say.
Kylo has absolutely no reason to see Han as a ghost or whatever the fuck that was. Han's not a force user so he absolutely cannot just come back from the grave. If this was some hallucination brought out by Kylo's own guilt it's just him forgiving himself which is a really funny and dumb way for him to be ''redeemed''
Speaking of redeemed Ben, he really didn't even get to do jack shit. He turned good, ran off to face Palpatine and died immediately after. What a waste.
The Knights of Ren still got absolutely no explanation of any kind. They were just absent in the trilogy up until now and then show up with no force powers or even lightsabers just to be fodderized by Ben to make him look good
There are sooo many other things, I'm sure, but I only saw the movie twice and have tried my best to forget it exists.
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Regardless of warnings, the future doesn't scare me at all. This is where the fun begins.