This room is a bit tricky. Try reducing the
gamespeed in the menu to make it easier.
First kill this monster by guiding it to
the bomb on the left.

The next monster should go to the right bomb.

These 2 monsters must be killed with one single bomb.
So remove both fruit blocks at once.
Try pressing the turbo key to go down faster.

There are 2 bombs remaining.
One for each monster.

To get the mystery just make a monster break
the block containing it.