Harpoon gun is challenging to aim on a moving target can only shoot one shot before it needs to recharge and needs to be used with teammates to down the ghost in most cases.
Its also the easiest gun in the game to overwhelm and kill as a ghost at any stage 1 on 1.
Honestly most of the hunter weapons seem to be balanced around teammates bringing in complimentary weapons and all have glaring weaknesses by themselves.
Shotgun is terrible for checking props because of the clip size and reload.
SMG takes a long time to check props because it only does damage after freezing props.
The melee weapons are terrible against either prop or ghost form.
Flamethrower lacks range and burst damage.
Project X overheats and lacks mobility.
Reaper you need to aim carefully and the explosion can be dodged if the ghost changes props before the bolt goes off.
Harpoon Bazooka does little damage on its own and is hard to aim, and if you miss you are really vulnerable. its basically a support weapon.
The default first gun has a small clip and slow hard to aim projectiles. Not great against running ghosts. Horrible for defending yourself at midnight.