Surprise! It's a volcano! This stage belongs to a flaming deer so it's not surprising that there will be some spots where you'll have to move quickly to survive. Come meet an interesting new enemy. If you come back here after defeating Flame Stag, you can get several otherwise-unreachable 1ups.
Beetron is a beetle. It will charge forward when X is directly in front of it. If it hits certain breakable parts of walls, it will destroy the wall and explode, clearing a new path. This one has another use.
Hop on top of the Beetron and it will carry you straight up to a platform with the sub tank on it. Hooray! Go back down. Dash jump from up here and use a charged up Speed Burner to reach the 1up on the right, if you've already cleared this stage. You can also try a charged up Strike Chain but it's not worth the stress.
Grab the thin wall with the items behind it and let the Beetron smash into it. It'll destroy itself and the wall, clearing a path. Zig zag up past the Barite Lastars. Head right until you see an intimidating wall of fire. It will start to rise. Don't let it touch you! Ignore the 1up if this is your first time here. You're after something better.
Ignore all of the items you see on your way up. When you find the heart tank behind a Bar Waying, get close and use the Spin Wheel to quickly take it out and grab the heart tank. Proceed upwards as quickly as you can.
Once you reach the top, the volcano will erupt. Ignore the globs of lava, they don't actually hurt you. You can grab the health on the left if you want, then wait for the lava to subside before heading right. These pillars in the lava will sink when you stand on them, so quickly hop from one to the other until you reach the next part of the volcano. Another Beetron can clear a path to some more items, though you can get them without the Beetron's help.
There's another breakable barrier for a Beetron up above here. Get in there and go up. You'll find the next door.
If you've already beaten Flame Stag, climb up and dash jump to the right and use a charged up speed burner for another 1up. Otherwise, jump from pillar to pillar all the way to the right. There's a narrow vertical passage here. The gas from these pipes won't hurt you on its own, but a new enemy can put it to use.
This flying squirrel has a flame on its tail. It floats down the tunnel, sometimes stopping to throw tiny fireballs, but the flame on its tail can ignite the gas from the pipes. These fires will burn themselves out after a little while and Morgun itself is weak. Head up dealing with the pipes and Morgun as you go. Eventually, you'll reach the boss door.
This guy loves to bounce around his vertical-shaped arena, but he's easy to lock into a predictable pattern if you can exploit his weakness.
The Hard Way
He'll spend a lot of time bouncing off the walls, first up off the screen, and then down. You can go up after him if you want, but don't get much higher than he is. If you're high enough on the wall, he'll charge up after you with an attack that's difficult to dodge. Jump up along with him, shoot him, then drop down and shoot him again. He can also charge along the floor, leaving a trail of fire behind him. There's also the matter of the fireballs he can throw from his hands. When he's descending from his wall jump, either dash under him or dash jump away from him to the wall, then dash jump off the wall to get back in the game and hit him with a charged shot. It's stylish and a bit tricky, but effective. Knowing when to be on the wall and when to come down will help you avoid his ground and jumping/climbing attacks. Once he takes enough damage, his fire will turn blue and he'll begin to move faster. He'll also gain the ability to uppercut you during his dash attack, and maybe even grab and slam you, so perhaps you should avoid that attack. Just a thought.
The Easy Way
Flame Stag is very vulnerable to Bubble Splash. He'll always follow damage from this weapon with his fireball attack. He'll throw one low one, which you can jump over, and one high one, which you can dash under if you're far away enough. By the time he's finished attacking, he'll be vulnerable to another Bubble Splash. He won't last long against this pattern. His fire won't turn blue if you defeat him this way, either.
A quick-moving fireball. A pretty basic weapon when not charged, but the charged version will send X flying forward. This is necessary for some collectibles, including a couple of 1ups in this very level.
Remember that heart tank on top of the wall of spikes in Wheel Gator's stage? Now you can go get it. There are other upgrades that need the Speed Burner to reach, but we haven't seen them yet.
NEXT: Morph Moth