>>718536795
1. they're very well written and funny. That's a bar 98% of indie games can't beat for some fucking reason
2. The game's visuals are unprofessional but charming in a homestuck kind of way. It just looks simple, but not *ugly*, like Nidhogg 2 or big rigs.
3. Even if the game is kinda ugly and ms-paint like, the character designs themselves are charming and cute in a silly kinda way. Compare UT/DR characters to some shit like Penny's Big Breakaway, which has good graphics but ABSYMAL DOGSHIT TASTE in character design and you'll understand the difference
Basically, Undertale characters have soul.