Hiyarika is the token cold stage of the game. It is also the first to introduce five sections instead of just three, meaning there are 25 bases to destroy on this stage. This becomes the norm throughout the rest of the game. The standard shop of the game doesn't offer too much in the way of upgrades besides the Jet Engine. You may wish to save your money, however. This round hides not one, but two secrets, and one of them is a shop that can help boost Opa Opa's power tremendously. But first you'll need to find it.
The bases in Hiyarika are called Kachikoron. As expected, they are stronger than bases from the previous stage, but not by much. It takes nine normal sized bombs to clear them away, or five big bombs. You will find them scattered around the stage at various heights. The two extra sections means more bases to destroy, but it also means more $500 bills to collect. Don't let any slip through your fingers.
Ancles fly out from the Kachikoron bases. They very quickly rise or descend to the same height as the Opa Opa, and then they slowly drift left or right. They are most dangerous when you are immediately above or below a base.
Cocos appear in groups of six. They appear from the bottom or top of the screen in a single file, approach the opposite side of the screen, and then perform a tight U turn, returning back to the side of the screen they came from.
Doras appear in a tight formation of six, flying across the screen to the left or to the right in a sine wave. Since they don't veer very much from the height they arrive, it's fairly easy to pick off all six for a $200 coin if you shoot fast enough.
Mappos are among the most dangerous enemies to deal with in this stage. Six of them appear on the right or left side of the screen in a C formation. All six simultaneously shoot at Opa Opa before advancing across the screen to the opposite side. Not only must you dodge the six bullets, but you must also punch a hole through their formation to get to the other side of them.
The boss of the third stage is called Iceburn. He is a giant block of ice that moves around the screen in diagonal directions only. Whenever he reaches one edge of the screen, he bounces off of it and continues his diagonal trip around the screen. He occasionally fires off a chunk of ice at you, so it's important to keep moving, not only to avoid the ice, but to avoid Iceburn himself. There's not a lot of strategy in this fight. Simply stay far away from him while you shoot at him as quickly as possible, and reposition yourself when he crosses over from one half of the screen to the other. As you shoot him, the surface of the ice gets progressively cracked until he ultimately shatters. From the ice pours coins and a few dollar bills that you should claim as quickly as possible.