[spoiler=The Secret of Kells]
The basic story is based on the creation of a very famous page in a famous illuminated manuscript whose pages survived the Viking raids. The art style and colors are obviously influenced by the style of illuminated manuscripts, and it's a really breathtaking visual experience all around:
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The animation is also really beautiful and smooth and there's this really awesome sequence where this white ghost-cat kind of ghost-wisps down a dark hallway and it just lOOKS REALLY COOL. Just watch it. Trust me.
Soundtrack is also beautiful? Holy poops. So good.[/spoiler]
[spoiler=Song of the Sea]
I LOVED THIS ONE A LOT. It's about the myth of selkies, and the main characters are an adorable little babby selkie girl and her adorable little very-realistic-depiction-of-an-older-sibling brother. I'll just let the screencaps speak for themselves.
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The soundtrack for this one was also super great because it was around a central tune (the song of the sea, obvi) and it's just so cohesive and nice. [/spoiler]
All of his works have the final product looking exactly like concept art? I love it so much. Each one feels like it has a very specific artistic direction and it's beautiful. They interact with myths and really make you feel like you're in a fairytale- in the slightly eerie, slightly creepy, definitely mystical, and beautifully serene sense.
They're also fairly short films, so...
ANYWAY! Highly suggest. If you have seen, please come fangirl with me because I get very emotional thinking about how these films make me FEELLLLL