That is a really hard question to answer.

Another Medium? Asgore? Finale?

https://www.youtube.com/watch?v=mqzBv3FYpr0

Everyone Bonetrousle!

NYA!!!
I SHALL COUNTER IT WITH MY SPECIAL "RETRO" ATTACK!!!
https://www.youtube.com/watch?v=Keqp4IFXdNQ

critical pets! :O

Please, everybody! "MERCY" (ó.=.ò) <--- is a Pacifist who likes eating spaghetti, too.

BONETROUSLE!

Death by Glamour, I think.

There are a lot of good ones.

His theme (slow)
Hopes and Dreams
Dummy!
Megalovania

And more :)

Asgore, definitely. The whole soundtrack is fantastic, but I just checked my play counter for the tracks and realized Asgore's plays combined add up to the rest of the soundtrack for myself. XD

Megalovania
I don't know what's the reason. I felt it's another great 'Secret Boss' bgm. Very unique since it can remix into various style and maintain greatness.

DUMMY!

Undertale

Because it's an acoustic and emotional song.

This.

For some reason, Death By Glamour! Gotta love fabulous robots XD

All of them, all the music... there's not a track I get tired of listening to.

Dogsong, because I love retarded shitposting dogs.

My answer to that question is "yes". Really, probably Hopes and Dreams. Then maybe Heartache.

I haven't listened to the OST in a while because I don't know if my heart can take it, but I'm pretty sure Hopes and Dreams/SAVE the World have the most plays out of any other tracks according to my Winamp. :P

Death by Glamour!
Especially this cover: https://www.youtube.com/watch?v=KHhe8begOQk

...or Heartache... depends on the day x3

Hopes and Dreams really emotionally moves me.

Definitely Hopes and Dreams. I listen to that thing on loop when I need a burst of energy!

https://www.youtube.com/watch?v=BEWOTdVnnZ8&index=2&list=PL9kZV3HvUZu8QciVsyr48fASM4P7cfKQh

Bergentrückung and Asgore (you cannot listen to one without the other) because you can just hear that he doesn't want to fight you. Your Best Nightmare and Finale (see previous statement) are a close second.

So much good music, it's hard to choose.

The ones I can give explanation to are Heartbreak/Asgore because they have the same melody but in different time signatures: Heartbreak (6/8) Asgore (4/4).

Ghost fight, Dummy and Spider Dance evolves from one to another. Ghost fight is the starting song, Dummy is the remix of Ghost fight and Spider Dance is a remade version of Dummy.

And Megalovania goes so well with san's fight.

The thing about this soundtrack is that it reuses melodic bits to tie themes and characters together. It seems familiar because you've heard the same tune over and over again throughout the game, but it's presented differently each time. The music also conveys strong tones related to in-game material, which I am an absolute sucker for.

Fun fact: The word's leitmotif!

itll take less time to say which songs i dont like

Megalovania will always be my absolute favorite just for listening to, but if I had to pick a favorite for overall reasons it'd definitely have to be Battle against a True Hero. That bassline just... always gets me.

Gotta say it's Hopes and Dreams'.

It had to be some of the most inspiring and optimistic final boss music I've heard in a long time. Really gets me pumped up when I hear it!

Probably Heartache. Loved it since the demo. It's a great tune, a really cool sound combining the chip tune and sort of digital strings, and I feel like it's the first big moment in the game where you know things are going to be different.

Spider Dance. Hard to top that.

high five there dude :D

The main theme, Undertale, though I'm fond of this mix of it with Dragonforce:
https://soundcloud.com/wendyfag/thr.....core-and-ruins

Also if no one linked, see how many of the connecting themes you picked up on:
http://feralphoenix.tumblr.com/post.....ecurrent-theme

Megalovania is one of the best battle themes in any game.

Reference: https://tobyfox.bandcamp.com/album/.....ale-soundtrack

I have the bridge part of Enemy Approaching as my ringtone.

Dogsong is freakin' adorable.

Temmie Village should be my walk-around-town song for daily life.

Thundersnail is kinda high energy.

Death By Glamour as well as Can You Really Call This A Hotel etc etc are pretty catchy too.

Either Memory or Your Best Nightmare.

Memory is really simple and pleasant while Your Best Nightmare is very intense with catchy chiptune-y breaks for the different soul minigame segments.

I love the soundtrack and my favorite seems to constantly change. Though Ilove Megalovania and Bonetrousle , Muffett's theme could be my favorite quickly followed by Death by Glamour

Hopes and Dreams definitely. Though all the songs are absolutely wonderful as is the game.

Muffet's theme was one of my favs.
https://www.youtube.com/watch?v=Njw007Zdgw0

though i'm tied for Undyne (genocide version) and Asriel's (true pacifist) for second.
https://www.youtube.com/watch?v=xX_imE4zKD4 and https://www.youtube.com/watch?v=Fh4aMniXMAw

Sans' Megalovania music is third. :)
https://www.youtube.com/watch?v=ZcoqR9Bwx1Y

My favorite?

Another Medium. https://www.youtube.com/watch?v=dNN0HyO3rM4

There are lots of great songs in this game but the Credits theme "Last Goodbye" simply combines so many things in itself. It's like you just finished the game and all the feels are coming up. Even if you didn't play the game yet and just listen to the piano, it's just grabbing you. Argh, it's just so epic. (-^.=.^-)

Hopes and Dreams
Megalovania
Why? Cause it's catchy any i could listen to it for hours =3

Megalovania, simply because it's the one I listen to the most often.

But there a ton of good songs of that OST.

Another Medium ! :o

Undertale's title theme Undertale is absolutely beautiful.
https://www.youtube.com/watch?v=2OqigCz2S1w
My second-favorite theme is probably ASGORE, which is epic, yet tragic:
https://www.youtube.com/watch?v=pcamjcoRmrQ