This review encompasses both seasons of the main show.
Code Geass is ultimately a decent show, but with lots of problems and is a far cry from being a great one. At times, its plot is schizophrenic, tonally inconsistent, its characters bipolar, and its structure a mess. Other times its amazing, novel and engaging. It feels like it had 3 different directors competeing with one another. That said, every good story has a good beginning, a good ending, and interesting characters. On that note, Code Geass is a success and is worth a watch.
The narrative is often a mess because they end up trying to cover the perspectives of a dozen people with cuts lasting only a few seconds. The only purpose of which seems to be to remind the viewer that they exist. Further, the naratative shifts between a gritty mech war drama, a slice of life comedy, and political intrigue drama fueled by a borderline incomprehensible supernatural meta plot of killing God.
The mech battles are animated beautifully, yet are a let down. The battles are always decided by whoever brings a higher tier mech to battle. Equal tier mechs are a tie unless someone did something stupid like neglect to charge their mech before fighting. When you notice the pattern, it takes away most of the stakes to the fights, only to be briefly reawakened by the rare exceptions to this rule.
The main character Lelouch's primary attribute is his strategic genius. Yet only roughly 1/3rd of his plans succeed. He gets outmaneuvered and defeated another 1/3rd of the time. And the last 1/3rd he gets defeated by someone showing up with a brand new higher tier mech that mops the floor with his army. When he loses he acts like a petulant 3 year old child, but can immediately change to a cackling villain, then to a suave hearttrob, and then to doting big brother.
The other characters are typically interesting, but some of them are practically bipolar. A character might get introduced as a cackling mass murdering villain, only end the show as a perfectly normal realistic leader. Another may go from bad guy, to good guy, to almost bad guy, to good guy again with very sharp transitions between the two.
I have a special complaint about the intro and outro songs of the 1st season. I've never heard worse in an anime. I don't expect much, but dear god, it actually detracted from the show and made almost drop it. Compare and contrast with something amazing like Cruel Angel's Thesis. Granted, its not fair to compare to possibly the greatest theme of all time, but it really showed to me the effect of a good intro. One brings you in and get you engaged while the other drives you away. I'd honestly rather listen to a youtube commercial about how I am carrying 20 lbs of toxic poop in my body, or listen to a screaming cat backed up by 3 monkeys playing the accordian than hear the first season's theme again. The 2nd season's music improves, but it only achieves serviceable mediocrity.
With all those complaints, you'd think I'd rate it much lower. Well, despite all the stuff it does badly or wierdly, it still manages to tell a decent story overall. The first 10 or so episodes are great. The last 10 or so episodes are pretty great. I'd almost like to rate it lower, but I feel it offers enough to the average viewer to be worth the score I've given it.
End Verdict: A decent watch, but one I almost dropped halfway through and would never watch a 2nd time. Could have been amazing with better direction and editing.