There are two kinds of great games, the ones that you delete from your hard drive after playing, and the ones that you want to keep forever. Cave Story (洞窟物語, or Doukutsu Monogatari), a free game of less than 1MB in size, is without a doubt the latter type.
The game was translated by fans into English, Chinese, and many other languages. In 2008, NICALiS announced that it will collaborate with Daisuke Amaya to release Cave Story on the Nintendo WiiWare with updated graphics, music, and more in 2010.
A brief overview of the story complete with screenshots. Obvious spoiler alert.
Quote (the protagonist) starts in a cave. After taking the Polar Star (a gun) from the sleeping hermit gunsmith (without permission, hah), Quote heads out, killing every single living thing along the way.
After arriving in the Mimiga Village, Quote sees two Mimiga, King and Toroko, arguing as to whether to hand Sue (apparently another Mimiga) over to the Doctor (Date), who has been kidnapping Mimiga from the village (and spreading terror in general).
Quote then encounters Misery and Balrog. Both mistaken Toroko for Sue. After kidnapping Toroko, Balrog decides to teach Quote a lesson, but instead is taught a lesson by Quote.
After informing the villagers of what had just happened, Quote goes into Arthur's house (Arthur is Toroko's brother, and hero of the village, until he was killed by the Doctor). This place will become the main hub that Quote uses to teleport to various zones in the game.
Quote goes to the Egg Corridor to look for Sue, arriving just in time to see Sue get taken away by a enraged Mimiga named Igor.
After stumping all over Igor, Balrog arrives to save the day, only to end up getting beaten yet again.
Quote finds out from Sue that her brother is trapped somewhere in Grasstown and goes to find him. Unfortunately, Sue's brother, Kazuma, is trapped inside a shelter and can't get out. Yay, more work to do. Quote goes around and finds a robot that seems quite hostile...
...and proceeds to get stomped by Balrog. Misery appears, not happy that she captured the wrong Mimiga earlier, turns Balrog into a giant frog. After fighting off Balrog, Quote pulls the poor robot out from the floor. The robot proceeds to ask Quote to bring it the right ingredients so it can make an explosive to help Quote break open the shelter's door.
After freeing Kazuma, Professor Booster appears and informs everyone that the doctor has located the red flowers, which can turn a Mimiga into a bloodthirsty fighting machine (kind of like Igor). So to stop the doctor, Quote goes to the Sand Zone in hopes of getting to the red flowers before the Doctor.
After entering the Sand Zone, Quote encounters Curly Brace, a (female) robot much like himself. Curly Brace thinks Quote is there to take away the Mimiga children, tries to defend the Mimiga, and fails. Good thing Quote is a good guy.
After beating Omega, Quote finds Jenka, a powerful old witch and apparently Misery's mother...uh huh? Jenka will only give Quote the keys to where the red flowers are stored if Quote can find all five of her puppies... yay, more work.
Although Quote manages to find all the puppies, Balrog is one step ahead and takes the key from Jenka. After chasing Balrog to the storehouse, where the doctor and Misery forces Toroko to eat some red flowers, the King appears and tries to save Toroko, only to get beaten by Misery. After defeating a frenzied Toroko (who dies), the King dies as well and gives Quote his super cool sword. Before Quote can celebrate, Misery appears and sends both Quote and Balrog to the Labyrinth, the "dump" of the island.
Quote finds his way to a clinic, where he finds an injured Curly Brace, who was also sent there by Misery.
After defeating the "ghost," Quote returns to the clinic with Cure-All for Curly Brace.
Going a little bit ahead, Quote encounters one of the harder boss of the game, Monster X...
...which turns out to be a cat...
After locating the stone that's blocking the way out, Balrog appears. After getting beat once again, he helps Quote and Curly Brace to move the rock away (don't tell anyone he helped them, though!).
Quote, backed up by the awesome Curly Brace, makes his way deeper into the Labyrinth.
After making their way through a corridor with a lot of computers and shutters, the two encounters the Island Core.
The Core is what's keeping the island floating (yes, it's a floating island). After defeating the core, Misery and the doctor appears and teleport the core back to their lab in order to keep it alive (so the island doesn't fall).
Quote and Curly Brace are left to drown. To save Quote, Curly Brace gives Quote her oxygen bubble, sacrificing herself in the process.
Quote uses the tow rope and carries Curly Brace through the Waterway.
Stopping at a Waterway Cabin and draining the water from her in the process.
To get out of tehe Waterway, Quote needs to beat Ironhead, a character from Pixel's previous game Ika-chan
If Quote beats Ironhead without getting hurt, he gets greeted by a swarm of Ika-chan!
Quote finds himself washed up in the Mimiga Village.
Story update. The Doctor has captured all the Mimiga and is forcing them to help him cultivate more red flowers. The reason the Doctor is so powerful is because he got his hands on the Demon Crown, which grants its user power as well as the ability to command Balrog and Misery.
Quote goes through the destroyed Egg Corridor, fighting Sky Dragons along the way.
Kazuma then appears and offers Quote to run away with him.
And off they go!!!
A few months later, the Doctor, with his army of Mimiga, invades the world. The end.
Or not. Choosing not to run away, Quote climbs the Outer Wall to reach the Plantation.
Inside the Plantation, Quote meets Curly Brace, who has lost her memory.
Quote explores the plantation, finally ending up in a teleportation room. Before he could do anything, he gets caught by a Droll (guards).
After getting caught and locked away in a cell, Quote finds the letter Sue left in his pocket, and escapes to meet Sue's mother, who asks Quote to collect various parts for her so she could build a rocket.
Quote does so, and the rocket is complete to carry Quote to the Throne Room to stop the Doctor.
But before going, Quote goes to collect some extra weapons, and help restore Curly Brace's memory by bringing her a special mushroom.
Now Quote makes his way through the Final Cave.
Brutally beating anything in his way.
Phew, that was hard.
Quote fights Misery, wins.
The Doctor has taken the red flower's power and made a red crystal, which not only can affect a Mimiga, but can affect humans as well. Quote proceeds to fight the Doctor.
The Doctor loses control of the crystal, and becomes transforms into a new form.
After beating the Doctor, Misery appears and asks Quote to take Sue leave the island. Before any deals could be made, the Doctor appears again, transforms Misery and Sue into monsters, and merges with the Island Core. The final boss! Quote, being the protagonist that he is, wins, of course.
After beating the Undead Core, the island begins to collapse. Quote and Sue run to the edge of the island and jump. Kazuma and his Sky Dragon catches the two.
Everyone else escapes on the helicopter they originally used to come to the island. The End.
If by chance all the requirements have been met, Quote gets to brave the extra level Holy Cave, and gets to fight the hidden boss Ballos.
After Ballos is defeated, Balrog saves Quote and Curly from the collapse cave, and the three live happily ever after.
Wait... is that Misery?