Loki's Labyrinth was originally the Tudor themed maze of the Amazing Mazes. Whilst the other two were demolished to make way for Vikings' River Splash, the Tudor hedge maze was rescued, and built around... which is part of the problem. Whereas before the maze had an open, 'separate-from-the-rest-of-the-park' feel, it now feels somewhat cramped, which is a shame. Having said that, it's great that they decided to keep it, as it would have been sad to see all three mazes disappear.
If you have a few moments to spare, take a look. Mazes are always fun, after all, and it's a nice break from the hustle and bustle of the rest of the park. The views of the park from the central viewing platform aren't bad either.