its you vs sans and chara. by the way, to attack sans, press "z" on the fight button and then press "f", do the same except press "c" to attack chara. to act for sans, on ACT press "x", for chara press "v". sans talk is "s" and pun is "p" chara talk is "t" and chocolate is"a" arrow keys to move cheats ORQDSS NMD TN BTHVTD HMST SORQD ORQDSS TWN TN GDK DMTHRQKY ORQDSS TGRQDD ENRQ HMVHMBHAHKHTY (its a cipher, decode it to see what it is >:))
the songs are death waltz (U.N. Owen was her?) and megalovania. to kill sans, wait 10 turns and then attack him btw this took ages to make