Making a shooter without bullets through the use of a camera is a solid idea. Having to use the zoom to get a better shot is great too. I think if the ghosts were more of a threat it would add a bigger risk/reward situation to picking your shots. Also, the levels are fairly empty; obstacles are another thing that would add more challenge to composing your shots.
It's a shame you weren't able to add music in the jam version as it would really help with the game's atmosphere (being set in a graveyard and all). Good transitions between levels. I liked the way you implemented your tutorial as well.