It's probably not worth trying to sell the game to one person by openly talking about a twist the game pulls with its mechanics.
Not every single thing in this game is such a massive spoiler that it has to be hidden. Even the trailer shows an oddity of the gameplay mechanics with an attack that heals instead of hurting you, and changing the size of the little dodge box. I've known the game would change up the mechanics of fighting the very second I saw it because it's not very hard to piece together that it wouldn't always stay the same.
The thing I mentioned is like 30 minutes into the game, and it's not a even really a "twist" that compromises the story or anything.
I seriously don't understand the massive spoiler culture. But what do I know. I'll spoiler-tag it, just for you.
Also you can think the gameplay is dull for whatever reason but that doesn't mean it's unpolished. The gameplay is actually really good, though.
Major issue for me: I have trouble distinguishing the highlights in the combat menu (highlighted is yellow, not highlighted is orange). There's a reason why so many RPGs use massive pointers and/or those little select frames for their highlighting - to make it so even a blind and colourblind bat like me can see it. Mother 3 has a similar way of highlighting, but there the highlighted option is bright white with orange symbols, while the deselected buttons are greyed out, making it immediately clear where you are in the menu. This does not mark a polished game.
A friend of mine had issues setting up his joypad (it randomly decided to not take directional inputs), it took him 30 minutes or so to set up his controls and get them working. This does not mark a polished game.
There's other things that I noticed, though they were minor and, I'm fairly certain, have more to do with the game being made in Game Maker than anything else. One thing I remember that annoyed me quite a bit is that the game accidentally skips some dialogue selection prompts. When pressing the auto-complete button on the dialogue boxes, and since the option prompts immediately auto-complete, you sometimes pick an answer without wanting to. This does not mark a polished game.
Furthermore, and this is a criticism independent from the whole "oh it's such a polished game" remark, the puzzles seem more tedious than anything. They're not hard to figure out, and feel more like a "RPGs have to have puzzles, so let's also have puzzles" kinda thing. In the end, they just kinda drag out the game artificially, which isn't all that great.
I just do not believe that the gameplay is this game's strong point. And with a game where the storytelling is just absolutely great, that's completely okay. The gameplay serves its purpose, and it has its unique quirks that make it somewhat stand out. I just do not think that it's great. If you do, that's perfectly fine.
I'm not saying it's the worst thing ever, either. The game is absolutely playable, and my issues with it are, well, lack of polish. Minor stuff. And I suppose that's okay.
There's more than just black and white. I just don't find the gameplay to be particularly interesting.