kind of a minor thing but:
- sometimes knockback is annoying and it'd be nice to be able to disable it
- modifyable iframes probably doesn't have much practical applications besides occasional anti-cheese but it'd make for interesting level design elements
- high iframe amounts can be used as a makeshift invincibility power up
- ideally 0 iframes would allow you to be in a rose that constantly damages you while still being able to be hit by other damage sources (but i don't know if this is how it would work)

"- ideally 0 iframes would allow you to be in a rose that constantly damages you while still being able to be hit by other damage sources (but i don't know if this is how it would work)"

It would turn the rose into Sans' attacks.
https://www.youtube.com/watch?v=Vr4IYjeplJA