here are some musics, adding more soon slow them down for genocide in total there should be 5 areas in the game.
NOTE: (almost) All areas have a boss battle. not all of them are the same for genocide. for example Area 3 (Waterfall in undertale)'s boss depends on which route you are taking. Pacifist or neutral: Undyne (name in undertale) Genocide: Undyne The Undying (name in undertale) same goes for Area 4. (Hotland in undertale) Pacifist or Netural: Mettaton EX (name in undertale) Genocide: Mettaton NEO (One-hit in the enmy is over, unlike mettaton EX, also name in undertale) Area 1 and 2's bosses are easy peasy, one hit on them and it's over. this only applies to genocide. pacifist or neutral gives you a real fight with them. they are not so difficult, and in area 1's boss, if you reach 1 hp, the boss will not attack you anymore. same goes with area 2's. Area 5 Dosen't have a boss fight. except Sans's fight. (name in undertale) It has to be the most difficult in the game. because on undertale it's the most difficult.