I think this is the start of a good game, but it's the very opposite of what I think of when I think "so bad it's good". It's neither good enough nor bad enough, if that makes any sense.
This falls firmly into what I've been calling the "mediocrity gap". In the immortal words of Anatoly Dyatlov: not great, not terrible. It's not awful enough to be hilarious and sporkable, but it's not good enough to be a truly good game.
The core gameplay is solid. A physics puzzler where you remove blocks to guide the ball into the goal. Simple but fun, and well-paced with new elements added in to keep the experience interesting. I'd be surprised if this hasn't been done before, but this is the first time I've played that type of game so it was fun and fresh to me.
I really did find myself missing quality-of-life features though. Things like pause, quick redo, being able to pan around the level. And the music was a bit loud and harsh.
In general it feels like an earnest attempt at a game that just needs polish. The fundamentals are there, it just needs things like aforementioned quality of life features, menus, some sound and graphical tweaks, that sort of thing.
As for the modifier, it very much feels like a casual mobile game. It's coherent and well done in that way, but as you've said, not retro.