Well, except throwing a sword i don't see a was to kill a enemy. The hitting-mechanism takes away 10 or more harts in less than a second if i try to kill a enemy in close combat. Not practically.
The next thing is ... why do i have to buy 4 gems instead of simply buying a sword for 4 coins ? Is there a reason for this ? I didn't found a gem on the map or from the enemies i killed ...
Last thing i found is a bug: the game can't be focused by clicking it.
For example: as i wrote this review the game lost the focus as the active element was the textbox. But as i tried to play again i couldn't move. Instead i wrote some letters in the review. The only way i found to get back into your game was using one of the buy-buttons. The same thing happened as i was combining 4 gems. The game lost the focus and i was only able to move again as i brought another gem. That needs to be fixed.
The idea ... why not. The total impression for a first try isn't that bad too. but the game needs a lot of polishing to be playable AND enjoyable.