Yeah I almost had that happen with me but I think I ended up watching someone play it. Still kind of regret it but at the same time probably wouldn't have finished it on my own otherwise and I atleast have Deltarune to look forward to now.
It's good in a way that isn't really expected - the only thing I can say without spoiling is it did something really different with things that had been there a long time.
Undertale is such a bolt of lightning. It both depends on its player having experience with traditional JRPG and having no fucking clue what it is. But when the conditions line up, as it did for many people at release, it was such a master fully crafted experience. But even the slightest amount of "it's good because..." really siphons part of the experience away.
Tbh, I played it for a few hours, didn't like it and don't understand all the fuss about it. Does it get good later?
I was at a point, where I was going through a cave with a castle in the background (it was a few years ago), it was probably some kind of riddle, but I couldn't be bothered.
Is it worth going forward or did I see enough to just say "it's not my kind of game"?
Or at least don't do anymore than choose your preferred platform and then buy it. Its available on Windows, Linux, Mac, PS, Xbox and Switch but not on Android or iOS.
Its a couple of bucks on steam at the moment, included in PSN if you do that, or full price everywhere else.