Frisk is so adorable in this, I love your interpretation of older Frisk, especially here. The background is beautiful, Frisk is cute(chubby Frisk is best Frisk), I do have to mention that Sans seems a little off in this - giraffe neck. Also, Sans doesn't have lips. It's even pointed out in the game that you wouldn't want to kiss a skeleton for that very reason. .3.
Still, nice!