By slasher standards this is rather bland and boring. I think the author just googled how to write a slasher story and then put in the minimum amount of effort.
Step 1. Introduce killer with a strange appearance.
Step 2. Make that first kill memorable.
Step 3. Introduce a group of victims that will be killed off in crazier and crazier ways.
Step 4. Hint that one of them in the group will be the lone survivor.
Step 5. ????
Step 6. Profit.
It's total paint by number with this manga. Though I will give credit where credit is due, the melon baller to the face was sort of creative. That is unless the author stole that from some where.