Like many others here, I was drawn in with the charming opening, the fun battle system, and the enjoyable opening. I quite liked the first world, and there was a great deal of humor in the subsequent stages. Even the presence of stages felt great. What stopped me halfway through was the *Things,* which, due to their scarcity and your limited carrying capacity, drag the game to a screeching halt.
I was thoroughly excited by the adventure game comparisons, but that is utterly invalid when every puzzle allows you to carry one or two items all the way across the game world and you only find out if it is at all useful after you are deep into the area where you need it (worse for bosses). Sure, there are hints about what you need, but I don't want to waste my time entering fights, seeing what I need, and then either losing or chipping away a win but still being made to feel like I chose incorrectly.
I also hate overly verbose RPGs, especially when accompanied by silent protagonists, and TTYD could have used a bit of trimming, but the characters were all terribly charming and funny. As much as I liked the opening, there wasn't anything else comparable at least halfway through the game. It felt terribly barren.
It's pretty, it can be fun (the basic battle system is quite enjoyable), and it has great music, but it just gets increasingly aggravating to play as you go on.