First, thank you so much for trying the game and leaving a comment :)
The game is set up that way, as this is a prototype/demo some of the quests cannot be finished, slaying the dragon is the last quest to be able to fight him you need some special power to do so ( think zelda; Dodongo's Cavern ;) )
Check the map and you will see how much is left to explore...
Support, rate and interest will get this game a long long way ;)