Welcome to our humble virtual abode!
All of the puzzles on the site are classified as to type, so my first suggestion is to go the the "riddles" page. From the main page, the category links all show near the top of the page, with riddles showing at the bottom rightof that list. As for the problem difficulty, each puzzle is rated by the puzzle submitter as to its difficulty level. This is shown as a small graphic to the right of the puzzle name with 1 to 5 small colored bars, with 1 bar meaning easy and 5 bars the most difficult.
Enjoy your stay here!