How do I get the treasure in the Lava Pools section of Ignan Ruins(2-3)?

As the last remaining secret treasure I haven't discovered in the Ignan Ruins, I am very eager to find riches in the Lava Pools. However, I'm struggling quite a bit, and I don't want to waste my precious health purchasing a hint.

Currently I have tried:

• Luring all of the bombs together(like a bomb party, or a bomb family reunion). This failed because the bombs hit an invisible wall when they venture too far from their spawn points.
• Hitting all the rocks
• Hitting all the rocks as many times as the fire pillars near them shoot up
• Jumping into the fire pillars that shoot out from the lava
• Jumping into all the lava I can find while craning my neck in a vain attempt to look for sekret passages
• Luring the bomb at the top-most platform into the bridge gap to kill it
• Running around in circles

I have NOT tried:

• Killing only bombs/fire slimes/bees/mushrooms since the jumping enemies are very suicidal and I'm too young to die from a frustration-induced stroke
• Killing all the jumping enemies by making them jump into the lava because this isn't Waiting For Godot
• Rubbing my belly and patting my head while singing because I'd feel silly

What do I do?!

The solution to this is to only break the barrels after you have cleared all of the enemies.

Naturally, the barrels are in your way at the start, and you can't exactly jump over them. Which means we need to take a shortcut.

First, clear out all of the enemies on your starting side of the barrels. So, all of those purple Mushrooms, a handful of Bees, and that one Bomb in the middle. Once you've got none left (Red slimes don't count), you need to move onto the central platform. Head straight east and jump to land roughly in the middle of a circle of Mushrooms. Now you're past the barrels!

You'll need to double back towards the barrels to catch a couple Bees and Mushrooms. Make sure not to break the barrels yet. As well, you should hopefully harvest enough magical gems from enemies to take out the Bombs safely. Once you clear the last enemy (it'd dispel the barrier, if this is your first time or a time trial), then double back and break the barrels. You'll spawn the chest near the entrance of the room.

Your prize is as follows.

Ferromin! That's... it. +10 Max HP, though, so use it to buy more hints!