Undertale for sure.

It has such a slow start, and meh graphics going into it. It took me 3 separate years trying to get into it, but once I got past the first 2 hours, man did the humour, characters and music blow me away.

If you’re worried you won’t get into it:

• The graphics start out rough to make the better graphics later on really stand out
• The slow start is actually them setting things up a whole bunch of things that pay off later, stick with it. (Also since the game is only 7 hours and there are multiple endings, you will replay it to get the other endings and notice just how much content is hidden at the start that you didn’t understand the first time playing it).