Yo, that's pretty wild. That'll most likely be very useful for casual Cuphead players. Might be useful for speedrunners too, but ultimately we gotta see if it's ok with the mods. Might be banned for runs and I don't think it's possible for PC users to do(unless there's another method). Pretty cool find regardless =)
Yea that attacks definitely too fast to react against. Your best bet is to anticipate Cagney going up or down with stretchy face after he is finished spamming seeds. If your already on top of a platform and he's getting ready to attack upwards drop down on the platform to avoid it. If your on the ground and he's going to attack downwards jump on the platform to dodge it. Hopefully this helps you out, Cagney is pretty tough to beat.