When I watched Year One a few weeks ago I didn't find it all that engaging, I also thought it lacked the "intimacy" of the comic. So, based on that I wasn't sure how The Dark Knight Returns would translate. Thankfully I really enjoyed it, really looking forward to Part 2.
I really enjoyed Year One, felt it transferred to animation really well. Especially enjoyed Brian Cranston as Gordon, good choice for a Gordon-centric tale.
The Dark Knight Returns Pt1 - I felt that this suffered more in translation to animation. Don't get me wrong, I quite enjoyed Peter Weller's voice work for the older Batman, but Miller's masterpiece is full of internal dialogue which the director had to shoe-horn in to the script. Maybe if you haven't read the comic it's less noticeable.
Also the plot device of using the media to push the story along - whilst fresh back then, does seem a little clichéd now as it's been long overdone. Not Miller's fault he was ahead of the curve tho.
It's still good though, these are minor quibbles really, and the adaptation also surprised me in that the material was interpreted just a little bit lighter in tone than my own reading of the graphic novel.
Seriously gagging on the second installment.