RETROZONE

*** BOSS FIGHT ***
This guy can be TOUGH. Defeating it will require a lot of patience on
your part. If you try to rush things, you will never win. It splits
into six pieces, only one of which can be damaged. This is the one
with the dark blue figure. The rest will hurt you if you touch them.
You will have few opportunities to do damage, and you must make each
one count. When it merges, the part you can hit will always fly from
the bottom right corner, giving you the opportunity to hit it as many
as three or four times. As it spins, DO NOT GET CLOSE. Stay in the
upper-left corner until it finished forming, then dash behind it to
the upper-right. Look out for the blocks of ice it'll drop (just
avoid the shadows), and move back to the left, in front of it, when
the coast is clear. When it splits again, the part you can hit will
usually go off toward you, giving you another (albeit riskier) chance
to hit. Repeat and be as cautious as you can. Eventually, you will
win. It is possible to kill it at level 21 without using the herb if
you watch the pattern enough.