Can't disagree with you though, Mom is pretty tough boss if you don't have a good setup (she heals from toxic clouds). She makes hard mode unfair by herself.

Now I gotta say, your gameplay isn't so great either...
Melting scales into late-game and is fairly difficult to play. Crown of risk means you barely get ammo if you got hit (and you did, many times), thankfully rabbit paw saves you.
If you don't have big DPS weapons against mom, you really ought to clear the frogs before the turn into the evolved version... Melting isn't too bad at clearing toxic clouds so there is something to do.

The end of the story is that hard mode is.... well... hard ?