This sounds pretty bad if it really is the case! :O The mouse support of the game is really limited and clicking things doesn't get you far. The game is meant to be played on either keyboard or a controller. Did you try the keyboard at all? Diagonal keys are used to navigate menus and the character, ENTER key is used to choose things and investigate, ESC brings up the menu and works as a cancel key and SHIFT is used for additional things like running, shooting with bow and arrow and backstab skill. Sorry that there isn't proper instructions in the game.
If the keyboard keys don't work either, then it's definitely a bug of sorts which I haven't heard about before.