I'd be curious to see a comparison of riddles by country.
Probably stuff like
1+1=?
The earth is ____ years old
etc, in the US. 
Puzzles are pretty decent, but kinda low-level? I mean I'm a guy that has would faq in adventure games puzzles at least a handful of times per games, but I've been able to figure out all the ones I've encountered in escape rooms so far even if it takes a few mins to go "aha!"
Or it might be the opposite that having grown up on hundreds of adventure game puzzles that are often illogical and can be hard as fuck that I'm pretty good at this stuff.
That being said the puzzles are much more like lucasarts/sierra use this thing on that thing to spell the answer rather than Layton-like logic puzzles, which is good because I'm kinda so-so on Layton puzzles. Like it's all obvious if you think about it, but you do have to think about it.
For example, like collecting blood sample tubes from different puzzles and putting them in a given-by-puzzle order (A->AB->O) etc.. and then figuring out that the number of samples of each blood type (5A->3AB->6O) is the combination lock 5-3-6, etc...
The one I did last night had a 5% success ratio mostly due to players being split into 5 smaller rooms alone, so your stuck in a room by yourself instead of having a team. But there's a person in the center that all rooms connect to and can exchange items between rooms through small windows. If one person is not doing so good they can fail everyone because they're all alone in their room and they need to solve puzzles to get items needed to solve other people's puzzles in their rooms. The individual rooms aren't super hard, but it's that dependency element that kills the success ratio.