Can't really compare the two.
If I had to say something, Undertale was an amazing experience with quirkiness that reminds me a lot of EarthBound, while Cave Story is a pretty intense game that got me to play games like Super Metroid, which is an amazing game.
"Just for comparison Uncharted 4 was 20x bigger than Splatoon 2. This shows the huge difference between Sony's first-party games and Nintendo's first-party games."







