1st time playing-none
2nd time-final boss is slightly different (can shoot pea pods)
3rd time-none
4th time-a boss based on butters? (Butter Mouth)
5th time-none
6th time-a secret fight involving text about decimals with byte value
7th time-none
8th-24 times-random easter eggs ([these stack]8th,dev room, 9th, bongos in dev room, 10th, Lunar is in the dev room, 11th, Pea is in dev room, 12th, butter mouth is in room, 13, Glitchface's face is invisible during the finale boss)
25th time-hard mode
26th time-secret Zero boss accessed after the final boss