Edugames are usually heavy on content and sparse on player systems. This normally lends itself to simple interactions like clicking and dragging items and characters across a screen. Additionally, most games that fit under the umbrella of edugames reach for the lowest common denominator to appeal to younger children and personal computers as the primary platform.
In order for these games to succeed the puzzles must follow solid game logic and character dialog must be interesting to the audience. Humor is the normal crutch of the genre, but recent releases from Telltale Games, like the recent Walking Dead Series take on a darker tone to the space and character exploration.