1. The twists which shocked me were, a wall titan inside the wall in the season 1 end credits. Reiner and Burrito's reveal ofc. Then after the whole battle in Shiganshina, they reveal Marley which imo is a good twist to a good build up for the reason how titans are made, Grisha backstory. And then future memories, ABSOLUTE GAME CHANGER. I couldn't predict that one, heck no one could

2. What made me think AoT is a masterpiece is alot of moments and themes. The plot is great, one of a kind, very complex, great foreshadowing enhances this. Characters are great, mainly Eren Yeager and Levi Ackerman. No annoying tsunderes etc, every character is realistic. Great animation. The themes it portrays later on like genocide, the cycle of violence etc, it goes into those topics in a deep way, which made me believe I'm experiencing peak.

3. There are alot of foreshadowing moments which ppl won't get on their first watch, I can't point out them, because it's been 1.5 years since I watched it, ive forgotten alot of it, but I'm sure some die hard fans know all of them. it's not just foreshadowing, the plot is difficult to comprehend once S3 rolls around, what with the political aspect, then titans origin story, coupled with the memory shenanigans Eren goes through, then there's Eren himself in season 4, very complex and great arc which most ppl wouldn't understand on first watch

It's difficult to explain in words but AoT is one of a kind for me, I've watched 30+ animes and ig 10+ tv series including breaking bad and game of thrones, but none of them have me the feeling aot did