>>713957802
in my opinion you understand Undertale lore like this:

- 85% of it is explained in a normal pacifist route
- 5% is explained in a neutral route or through specific interactions (for example you learn Flowey can save too if you kill toriel but load a save to spare her)
- 9% of it is explained in a genocide route, mainly stuff about chara, sans and flowey
- 1% can de discovered by autistically examining the game code and hacking it

there are some overlaps, for example genocide also explains flowey can save

that being said, that 1% of the plot you can discover by hacking, theres no overlap with any of the routes, its probably canon, i mean i dont think Gaster's name is ever mentioned in any route, but his existence doesnt contradict any of the plot, and that 1%, it has some interesting bits that seem to make a connection to Deltarune