Anyone who thinks that RPGM would be superior to Renpy as an engine for this particular game does not understand either engine properly.
Advantages of RPGM:
1) A movable sprite if that's your thing...
Advantages of Renpy:
1) Save at literally any point.
2) Scroll backwards in text
3) Less run around
4) Not inhibited by the RPGM image limit that is around 2000
5) More save files
6) Runs faster
7) It's free for creators
8) No useless NPC's that just say one thing and are meaningless
9) It will take up less memory
10) Often times if there is some small error it is less likely to be fatal. You can click "ignore" and move 1 step forward where RPGM loves to say fuck you, and crash right then and there.
Don't get me wrong. RPGM can be good if you want say a clothing damage system, and some combat stuff, and I like some RPGM games, but clearly this game is a much better fit for Renpy.
This is just straight nutty now. There's far more advantages than just "seeing a sprite".
For one, RPGM allows for a significantly more sandboxy feel as well as making it easier to hide content and make it unfold more naturally as opposed to Renpy which is nothing more than a VN and a literal non game. Examples are the mother walking in on the son changing or something, here's how it would play in both engines:
Renpy
1. Scene jumps to the Mother walking in on the son in an extremely linear fashion
RPGM
1. Game allows you to decide to go check up on the son allowing you to either find that scene or miss it entirely, which is what would happen in real life (allowing for more immersion).
I like the developers decision to go with Renpy and I hate most RPG maker games, but you guys are just being ridiculously bias in your comparisons. RPG Maker is used at its fullest when exploration is the focus.
The biggest flaw with renpy is how short the games tend to feel due to them being nothing more than visual novels that are extremely linear. 99% of the time I find myself just skipping most of the walls of text to get to the next scene because there's no gameplay or anything even resembling it to keep my attention.
RPG Maker has its flaws and so does Renpy.
For instance, Lida's Adventure, Sarah's Life, Annas Affection etc are all games that at face value, would seem to benefit from RenPy but I really don't think they would in practice and the exact same could be true for this game.