For $20 bucks Dr. Who Eternity clock has been very enjoyable. The chatter between characters has been great, and the storyline is something you'd get right out of an episode. It is still a bit buggy when you have the single player parts that require the computer to be the second player. The second player can get stuck places if you mess up the sequence of what you are trying to do and where you are trying to go, this can be especially confusing because in the side scroller format it becomes difficult sometimes trying to figure out where you are to go next. they have sprinkled in 3-D elements into the side scroller which make it more immersive and dynamic, but it can real confuse the path to where you are supposed to go next, and a lot of time the elements are obstructed by the simple way the camera wields itself. It can be really tedious to spend a bunch of time doing 3 or 4 of the same puzzle time, which is fine, but then to get past them and then die or have your partner die and have to start all over and do the puzzles again. It's not always like this, but I wish once you beat a puzzle in an area it was done for good. I am on medium puzzles right now and would kick it up to hard but it's more about the time they take as opposed to actually being able to complete them.
At the end of the day it's still a buy for any fan, casual or not. If you're not a fan it's still worth checking out especially if it goes discounted. Got some interesting gameplay features.