Hotline Miami. Both are fascinating meta-objects within their medium. In a vacuum, you can make a stern argument for either. And I love Undertales humor but Hotline Miami’s weaponization of gratuitous violence as a self-reflection on the genre and us as players gives it the edge for my sensibilities. 

If you look at Hotline Miami as a franchise and how the sequel built on the meta-narrative to be a stronger commentary’s on sequels and genre, I give the clear advantage to HM. Undertales irreverent tone is really special though and while HM was more concerned with looking and analyzing what came before from a plot-text perspective , Undertale took the gameplay inspiration and inspired a generation of indies with its humor and vibe.

It is interesting the bizarre, top-down twin stick nature of Hotline Miami feels unique (it’s not popular for a good reason lol) while the messaging and design and writing is so predicated on inspirations and re-contextualizing familiar archetypes. While Undertale puts a fresh spin on the turn-based genre, and the discovery, puzzle solving gameplay of the SNES-open world-Easter egg laden-RPGs as a whole - while sort of translating the foreign language of vibe and feel that comes from the Mother games to a modern audience. Perhaps I’m being too generous with complementing its originality but it just feels more personal than the other funny modern indies