So I've watched two anime about time travel so far and both were brilliant. Steins;Gate was particularly mind blowing. It was like this perfect combination of plot, animation and complexity. One day people are going to look back and use it as an example of how anime should be made. Some anime try to make their plot way too complicated. Personally I'm a big fan of complicated plots that really make me think but it takes a lot of skill to pull of really complicated plots convincingly. Sometimes it just results in the creators running out of good ideas and ending the story in a way that makes most fans cringe. Steins;Gate has a perfect level of complexity. The time travel itself was handled brilliantly. Another thing that stood out was the emotional impact. Steins;Gate really shines in this. By the end of the last episode you'll find yourself mentally exhausted from all the tension that was built up over the course of 23 episodes. I'm glad that I started watching it long after all the episodes were released. I can't imagine waiting as long as a week for the next episode. I think Steins;Gate is the animated equivalent of The Chaos Walking Series in terms of how well written it was. It was also really well researched. I was quite surprised to find out that a lot of the "conspiracy theories" in the anime was inspired by some real life events. Especially the story of John Titor. It was a bit creepy to find a Wikipedia entry on John Titor right after watching through the series.
The other one was a film. The Girl Who Leapt Through Time. Although it a less convoluted plot and less emotional impact than Steins;Gate it was brilliant all the same. Again, the concept of time travel was handled brilliantly.