I don't think the right-mouse-button attack worked for me? There was no animation, like with left mouse click.
Keep up the effort, very good for a first game :)
Maybe next time, there could be a ranged attack.
PS: Unity related issue: I think you have to click on your images in Unity and change the properties to "Compression: None" and "Filter: Point" for pixel art, but I'm not sure exactly what the options are called, haven't used unity in a while.