Undertale is known for many things -- being an RPG that doesn't make you kill anyone, its characters, and its soundtrack are a few examples.
Toby Fox, the game's composer as well as its developer, created the music for Undertale before getting into the programming aspect of the game. The music was there to help him determine where the scenes should go. Listening to the game's soundtrack, it's not hard to appreciate the work he has done here.
In my opinion, Undertale's soundtrack is one of the most memorable I've ever heard in a game. Because I loved it so much, I wanted to share my favorite songs after beating the game. So with that, here is my list of the top 5 songs in Undertale.
After dating a puzzle-loving skeleton person, escaping and making friends with a killer fish lady, and starring in a cooking show, a Romeo and Juliet musical scene, and a newscast with a robot, you have reached the core, directly under Asgore's castle. The core's theme has a definite air of urgency. You feel all the more drive to push forward and finish what you started when you left the ruins. Be it for the better or the worse. It fills you with determination (pun intended, har har).
It's because of the urgent feeling prevalent in this song that it has a place in my top 5. It's a song that I listen to whenever I need motivation.
4. Bergentrückung/ASGORE (Asgore's battle theme)
This is it...your ultimate quarry...the fight that has been hinted at for the entire neutral route -- the battle against the king of all monsters, Asgore. This song paints Asgore with a sympathetic brush. His convictions are absolutely unwavering. He must carry on the work he set out to do after the tragedy that struck his family -- no matter how much he wants to take his crimes back. You are the arbiter of Asgore's fate. You can forgive what he has done, or you can avenge the six other humans who died at his hands.
I love the tune and the percussion in this song. At the beginning it sounds like a chiptune before breaking out of the mold of a retro sounding song and going all out with the drums, synth, and piano. The chiptune still provides the base of the track. It gets loud in parts, quiet in others; in some of the louder parts you hear vocals. It all comes together to tell the story of the song's namesake incredibly well. Amazing stuff.
3. Megalovania (Sans' battle theme)
On its own, this song makes good headbanging material. But let's see you feel that way after almost getting outright destroyed before the battle against Sans even begins. Then the song starts, and that's the point when you should be thinking 'I'm thoroughly screwed.' Don't worry, he gives you plenty more opportunities for your game to end once the fight actually begins. He doesn't let up any. I can think of no better song to play as you struggle through several of the timelines in which you die, before getting lucky and seeing the one outcome in which you live, provided you don't give up first.
The synth really takes center stage in this song. It's incredibly in your face and it never lets up, just like Sans never lets up. It is everywhere in this song. The guitar rift and drumbeats are just the bit players.
This song takes the third spot because, while, it's definitely one of my favorite songs in the game, it doesn't have the same punch as other songs on this list (citing specifically Death by Glamour and Hopes and Dreams/Save the World).
2. Death by Glamour (Mettaton EX's battle theme)
Another synth heavy piece. I freaking love this song. It is a song I can listen to on repeat for hours. It's got an awesome rhythm, and the tune is incredibly catchy. It would not be a stretch for me to full-on dance to this song, I just won't do it in public. Just make sure the music doesn't cause you to lose too much concentration, or else your last moments will be absolutely beautiful. Because you'll die. Or not. The fight isn't that difficult.
Before I list what my top favorite song in Undertale is, I have an honorable mention...
Honorable mention: Temmie Village
Bob made me do it. Blame Bob.
1. Hopes and Dreams Will Save the World (Asriel Dreamurr's battle theme)
In my mind, there was one other song that could have been at the top. I couldn't decide between Death by Glamour or Hopes and Dreams/Save the World. I've always been a sucker for these kinds of songs. It's like in an anime, when it looks like the main protagonist is going to lose. The anime's main theme (or in this case, a remix of Undertale's main theme) will play when its revealed their victory was really never in question. They always had the upper hand. They'll fight this thing, they'll win, and they'll save everyone. Like a hero.
This is, hands down, my favorite song in Undertale. Besides being an awesome remix of the game's main theme, the song's use of orchestral and guitar arrangements make it unique. It was the song that, perhaps more than any other on the list, made me sit up and take notice of the power music has, how much it adds to a specific scene.
Don't agree with my top 5? Let me know down in the comments!