It wasn't on my list. I will defer that to the forum to come up with a compelling reason (other than making the game easier)
I feel like that's not a case of making the game easier, but making it more fair. The original Simon's quest has this issue too, as you have enemies that charge from above at fast speeds. Making a limited axe, or even a weapon that Simon swings over his head, makes a fight with these types of enemies a fair fight. I've always found the design around the axe pretty cool - It hits airborne enemies, but it still takes time to master, as it has a heavy arc. There's still strategy around using it.
A lot of enemies in your game seem awkwardly designed in regard to the arsenal available to Simon, again, a problem also present in Simon's quest; You get caught in moments where enemies from all directions kind of pile on top of you. I feel like a bigger variety of subweapons can help with some of the stranger enemy AI. As for some faster enemies like the harpies, werewolves, and eagles; have a more evident warning that they're about to do their attack. It's just so fast of an attack that it seems unfair sometimes. Also, the first time you see a new enemy, it's normally a good idea to have them do their attack once before Simon can reach an area they'd be hurt by it. You see this in a lot of the Castlevania games, it reduces the feeling that the enemy got a cheap shot.
A little touch up tip btw: I suggest making the black fade in when you enter new rooms a little longer, to prevent the player from seeing enemies drop into their places.