For a first game well done, you have something playable that is connected to the theme
some small pointers
1) Update the coins when you buy something, its easier to see what you still have
2) This is more a personal preference, but usually when you buy health you get the health. in this case it was max health and you still need to wait for regen. Again not a bat thing and can be intentional but i would call it max health then instead.
Good job