Just beat Undertale

I bought Undertale on my X-Box 1 for $15 and beat it in about 8ish hours, all in one day. I usually I can’t stand to play a video game for more than 2 hours MAX, but this game captivated me entirely. Plus I suck pretty bad at gaming in general. All I knew about this game was its 3 different routes, and of course the legend, Sans the Skeleton, although I personally much prefer Papyrus. I plan on completing the pacifist and Genocide routes too, so tips/rules are greatly appreciated! Gorgeous game, Toby Fox, and all the other staff! <3