Swim, Ikachan!

Swim, Ikachan! is an exploration platformer with RPG elements made by Studio Pixel, who would indeed go on to create his Magnum Opus Cave Story. The game is often cited as a 'practice' by Pixel in preparation for the aforementioned Cave Story.

In this game you are Ikachan, a young squid who lives in an underwater society constantly ravaged by earthquakes and facing a food shortage problem. He must explore the world, gain powerups, eat fish, and eventually face off against the tyrannical ruler Ironhead.

The game can be found here.

Tropes found in this game:

 * Big Bad: Ironhead.
 * Big Eater: Carry, which presents a problem with the food shortage going on.
 * Broken Bridge: Some parts of the cave are inaccessible until you talk to the right people, at which point a couple earthquakes will open up the paths needed to continue.
 * The Cameo: Ikachan and Ironhead would later appear in Cave Story. In a less visible way, the game also features an early version of CS's engine.
 * Cool Mask: Ironhead's mask, hence his name.
 * The Dragon: Carry, Ironhead's bodyguard.
 * Everything's Squishier With Cephalopods: The protagonist, of course.
 * Fake Longevity: Averted; It's not very long, and you can beat it in just over an hour.
 * Let's Play: There's one by Raocow.
 * Mismatched Eyes: Ironhead.
 * Puffer Fish: One of the food items that Carry has you Fetch Quest him is a globefish platter. Sure enough, when he eats it, he gets poisoned and has to relieve himself of his bodyguard duty.
 * RPG Elements
 * Schmuck Bait: There's a chamber full of fish that comes with a sign "Curiosity killed the cat". Indeed, trying to enter this chamber will shut the entrance and should you come without ability to thrust sideways, you will be left to die on a(n in)conveniently placed spike-bed.
 * Space Is an Ocean: Invoked in the ending.
 * Take Your Time: Even when  just as you've taken the last person save Ironhead into, you can still twiddle your thumbs and nothing will happen.
 * Under the Sea
 * Worthy Opponent: Ironhead considers Ikachan this after being defeated by him.