so, before the main game he sees that metal sonic lost to super sonic and decided to kill him, he satisfies with that and in the next fights (mk1 and mk2) he kills them, but after killing mk2 he goes a LITTLE insane (you can see it by his eyes) and mk2 leaves oil on his gloves

after that sonic.exe tells them that the game will start tomorrow and he will give them souls so they don't actually die and can be revived (tails, amy, knuckles, sonic and eggman himself), but before that, he liked killed mk2 so he decides to go for other survivors

first is amy, she got fooled by eggman (cuz of his 300 iq) and he crushed her head with 2 hands (she tried punching him without the hammer since she got double fooled and eggman got it at his hands), next is tails, he got fooled by eggman (cuz of his 300 iq again), cuz he thought it was going to be the act 3 green hill zone boss fight, but the platforms had spikes inside of them and they brutally killed tails, next is knuckles, he had a more brutal death, since he got grabbed by eggman himself, he tried punching him, but eggman was too smart (cuz of his 300 iq against again) and made a shield so knuckles punches won't do anything and he started chocking knuckles (ofc knux died bro like what), the last on his list was sonic (or he thought so), after killing knuckles he decided to build a teleportator which would teleport him to sonic, but it didn't go as he planned, sonic was too fast that teleporter was teleporting eggman behind, but eggman grabbed sonic's leg and cut it off, so sonic almost killed eggman, but eggman was too smart (cuz of his 300 iq against againy again) and made a clone, then he cut sonic's head and his code broke from killing all heroes and he became the third form and also he gone insane

after that sonic.exe tries to fight dr. ivo. killbotnik but sonic.exe brutally dies because his power is beyond impossible, since the only one who can beat dr. ivo. killbotnik is the eggman from a different universe, so basically eggman from sonic mania teleports to his universe using the phantom ruby and uses phantom ruby to kill him

NONE of the sonic.exes or killers at all can win him except for:

STARVED

BANDADO

or

Robuttnik.X