Bombing Busters

You can unlock the Ice Boss, once you completed all of the 5 regular levels from the Ice World.

Phase 1:

Ice Crystal Summon: He creates an ice sigil on one of the indestructible ice blocks and then a circle of ice crystals will quickly start to form around that block. Once the circle is completed they will explode after the boss roars. The explosion is an AoE (Area of Effect) attack that hits 3 tiles into all 4 directions from each crystal. The destroyed crystals will leave behind a snowy mist, which can slow you down for a bit, should you run into it. You can destroy these crystals with your bombs but it's best to just keep your distance from them as much as you can. If you get trapped by them, you are dead. It's possible to drop a bomb just outside of the circle to destroy one of the crystals and escape but it's extremely difficult to time.

Ice Block Rain: He'll move his body to create a quake that drops ice blocks from the sky in a circular pattern. The inside of the circle is safe but the outside will be covered in snowy mist, which can slow you down again. Try to anticipate where the ice blocks drop and then get into the circle asap. This attack won't kill you, unless you let a block drop on your head but the next attack will be hard to dodge if you're slowed down.

You can easily get hits in, whenever he is doing his Ice Crystal Summon. Focus on dodging when the blocks come down.

After 5 hits, Phase 2 starts and is indicated by the large ice crystals standing up on the back of the boss.

Phase 2:

Ice Crystal Summon+: In this Phase, the boss adds falling ice blocks to the ice sigil attack. They mostly are for cornering you but you can still get killed if one drops on your head. You need to be much quicker this time and make sure that you don't position yourself in a spot where you can't escape.

Same as last phase, just don't get cornered and try to time 2 bombs so the boss goes down quicker.

5 more hits and this boss is down as well.