I finished the game and here are my thoughts:
I really liked the custom graphics. Some of them certainly would need to be polished (tilesets and some objects sprites) but it's always nice to see custom assets. The sprites for the main character and the monsters were really well done, specially the battle sprites.
The battle system was something I wasn't expecting (and something you rarely see in Rpg Maker Horror games) and I have mixed feelings about it: while the mechanics were interesting and the main character protecting herself with her blanked was really sweet, I felt that some battles were a bit too hard, specially the shadows in the final section right before the final boss and the fire section boss (before I learnt the battle was easier with the skill you get from the snowman).
While I enjoy challenges and was determined to finish the game, there's a chance that some players will probably give up during these battles and miss the rest of the game. Difficulty is certainly something we devs have a lot of trouble with: we either create something that's too hard or too easy, and finding the right balance can be a nightmare.
The puzzles were nice and I didn't really have trouble with them. I did find some bugs: for example, in the final section, if you fall the character gets stuck in the air and you can't move anymore. If you save there, then your file is ruined. However, I think you mentioned that you had trouble with playesting for the game (or the lack thereof), so I understand why those bugs were present.
The story was sad but really interesting and I wanted to know more about the characters. I'm not sure if I understood the story correctly though (the grandma died of cancer and she was a very mean and hateful person and the mc was scared of her?)
Overall, despite certain bugs and the difficulty of the battles, I think the game was good and enjoyed playing it! Also, the storm atmosphere in the beginning was reaaally well done, I really liked that!