This is such a weird feeling poll to try and answer because of how different all the choices are, haha. It's like asking if we think you should eat a slice of pizza, a taco, a sandwich, or Undertale.
Of the four of them, Undertale feels like the one that's the most "impactful" on video games and the overall gaming community, though like others have said the style of the writing can be pretty divisive. A lot of the characters can toe a pretty tough line between being charmingly annoying, or aggravatingly annoying, depending on your personal tastes. Still, if it does click, then Undertale has some of the most memorable moments you'll come across in a game story. It became a phenomenon unlike anything else on the list and for good reason, but its quirks and popularity have brought out a lot of haters too.
Despite saying all that, ultimately I voted for Golf Story on the poll itself, mostly because whether Undertale's writing works for you or not is something we can't really judge for you. If you like golfing games at all, then Golf Story provides a ton of interesting challenges and scenarios and wraps it all in a nice presentation and some really great, funny writing that can probably be recommended more "safely" than Undertale's. Cadence of Hyrule is very good, but inessential, and I haven't played Axiom so I can't judge that one.
To those saying Undertale, I've wanted to check it out but I'm not big on replaying games for the most part (especially immediately after). Does it stand well with a single guideless first time playthrough?
A single guideless playthrough if you know nothing at all about the game is probably still worth doing, but I'll mention that with the odds of what that will likely result in, you'll have a good experience but miss out on part of why so many people feel the game's truly special.