This update is terrible and took too long, I am sorry!
First, RELEVENT MUSIC for this cave area (and I believe there are more areas with this music later on too):
http://www.youtube.com/watch?v=IsC4emfylsY

So after dying like a drowning idiot who drowns because I threatened to drown the drowning protagonist who drowned, let's go to the door. Press Up to open the door! Just like in real life.

The First Cave! Self-explanatory I would hope. Not seen: stupid blocks in the way like the one below the blue block to the right of protagonist. Protagonist can't destroy those blocks yet so let's go in the opposite direction!

OH SH-

Brain damage averted! Spikes are bad in video games, or so I have been told (which explains a lot about the VGAs). We jump past ground spikes and refuse to be dumb enough to jump high enough to hit ceiling spikes. One of the things that are underappreciated in games like this, the ability to control how high you jump depending on how much you hold the jump button.

Jumping over another floor spike and we see bats. Luckily these are not as annoying as in Castlavania or even Zelda. They move up and down. That's it. If you have trouble getting past the bats, stop playing. You have no chance. More important though is what's in the far left.

You jump to it, hit up (...or was it down?) and get...

...more health! Hooray! But enough about that...

We go down and right from there to continue our way to find...something. Maybe we'll find an alternate reality where Nicalis doesn't suck. Or a shoe. I think it'll be one of those two things. Regardless, more bats, water still sucks and we might need a head start.

Maybe next time I'll be able to show jumping AS IT HAPPENS.

But yes, jumped up on that block using a running start as the water kinda kills your normal jumping ability. At least there's a cute creature nearby. Maybe he can help!

Or maybe he wants to crush us like we're a Goomba. Run to the right!

Well, he gave up pretty easily. I'm not complaining as I have nothing to combat these demonic...bats and obvious attempts to be the next cute mascot Pikachu character. Now let's enter the cave from Aladdin and make lots of unfunny references to it!

The average reaction to screenshot LPs.

Finally, the first of many weapons! But before we can do anything else...relevent music:
http://www.youtube.com/watch?v=ebkcTZM0RnQ

Gold green haired guy is lonely. Estimated time before this is relevent to anything: 2 hours
Back with protagonist he has...

...killed enemies off screen...dammit. Well, enemies drop items. The heart refills some of your health of course but the triangles might confuse you.

Enemy hit me but I get revenge with this perfect example of the Polar Star weapon. Just keep pressing the button to shoot to kill these enemies. They show how much damage each hit takes too. This one just got "-1" HPed to death which is cooler than it sounds. More triangles so this is good.

There is a bar in the top left above the health bar. It is now a bit filled up thanks to getting the triangle from the enemy. Collect enough and you will go from Level 1 to Level 2, which upgrades your weapon a bit. This is not permanent though as losing triangles can make you de-level (and a lot quicker than getting triangles most of the time too) so try not to get hit too often.

...for some reason when you shoot the ceiling...it has Star Fox's shield from Brawl? I don't get it.

A few seconds of boring backtracking and a few more triangles later, and we're back to the save point room.