As is obvious from the summary this is my favorite show so I am biased in a sense. Although I have 0 nostalgia for this show (I didn't watch it til I was about 18-19) the first time I saw it I must admit I was so encapsulated by the show that I saw none of its flaws. So although I have no nostalgia for the some may say I am biased to it in a weird way as it was the first anime I saw that I considered "my favorite show" Understand one thing, this show is VERY flawed, it is far from perfect but I find what the show does is unlike any other and it gives me a feeling that no show has been able to give me since. Because of this I believe that the majority of this shows flaws are not a big deal.
~~~One of this shows flaws is also one of its biggest strengths. It is VERY ambitious. This show feels like it tries to do everything in a compact 50 episodes. This show deals with a terrorist plot, love, rebellion, racism, mech fighting, all while often taking place in a high school. Because the show is always trying to do so much it often skips around and Lelouch will do things that they don't show you on screen, but that you as the viewer have to put together that Lelouch somehow managed to setup things before hand. This can vary anywhere from a nice subtlety to the show to a "wtf how could he have possibly done that" moment. Another one of the shows plot holes has to do with the fact that the writers of this show constantly had to dig themselves out of holes they dug themselves into. You see this show has no manga so this show was very obviously still being made up while it was airing (similar to something like ATLA, etc.) The two biggest violations of this SPOILERS are when Vilvetta has amnesia by falling on a rock, and the whole debacle with Lelouch Dad and Mom near the end of the show. To address the former I suppose it is feasible that Vilvetta could've had amnesia by hitting her head on a rock, but its pretty stupid tbh, but I suppose I can get past it, it just feels like the writers forgot about her and then had to figure out what to do with her. The bigger violation is The scene with Lelouch mom and dad in C's world. So Charles geass', Nunnaly causing her to be blind and fronting that it was done by terrorists, but wouldn't that mean he knew what V.V had done? This whole scene is too confusing and convoluted to get into but as it stands it is the only real problem I have with the show. This also has quite obnoxious fan service and I COMPLETELY understand why people have such a big problem with it, but for me it never got in the way of how amazing the show was.
~~~This show is pure cinema. Everything this show does is bombastic and jaw dropping and it keeps you on the edge of your seat at every turn. From the amazing over the top but insanely diverse soundtrack, to the amazing quotables and dialogue throughout the show, to the great characters, world building and plot twists. This show has it all. Watching how Lelouch plans unfold and hearing how he feels about everything that happens is nothing but engaging and endearing and it makes you want to watch him succeed in all of his glory. This show also has really cool features that I've never seen any other show has, many people I know skip these but at the end of every episode, where most shows would give you a preview of what would happen next episode, Code Geass instead has Lelouch monologuing about all his thoughts on the current situation and what he plans to do about it and its just awesome. This shows dialogue is great to me because of how subtle it is and I constantly pick up new things and understand more on every rewatch of the show. This is something I feel every great piece of art should do, it should get better upon every viewing and with time. There are a lot of characters in this show but I feel the majority of them are great and a lot of the debates are so philosophical and psychological that it makes you really think deeply about what the subject matter they are talking about all means. Put one of the best soundtracks I've ever heard in an anime on top of that with amazing fight scenes, character development, world building, and just pure chaos, and you have yourself nothing short of a masterpiece. On top of that this show has one of, if not THE greatest ending I've ever seen in a show that will make it stick with you forever. I could gush about how amazing I find everything this show does for hours but to not get too repetitive and redundant I'll end it here. This show is a masterpiece and the most ambitious show I've ever seen, although I admit it would have almost certainly benefited from being longer, but as there were contract problems with the studio there was nothing to be done. I would recommend this show to anyone, just make sure you watch all of it or you might not get a good idea of what the show really is.