Cave Story is a game I care a lot for, as you might know. Back when I first saw the alpha/beta images that Pixel published on his website, many years ago, I couldn't help but wonder what this unpublished version of the game was like.

Naturally, game development can be a complicated process involving iterations of concepts and even removal of entire ideas. This page only lists some screenshots and images I've found throughout the internet, and sometimes my personal thoughts about the meaning of them. Lots of information are based on text sources (interviews, BBS, posts), though.

Cave Story Alpha/Prototype

Pixel was inspired by games he played in his childhood, and learned how to program his own games with the help of his dorm friend.

The game he was working on back then (1999), which I'll refer to as "Cave Story Alpha" for the lack of an actual title, was shortly abandoned after the beginning of development. The “Tokyo Culture Culture” event held in 2011 ( is the main source of information about this version of the game. When asked about it, Pixel said the game was about going from cave to cave to eat fruits and survive.

Here are some blurry images of it:


During 1999 and 2000, Pixel moved on to make another game called “Ikachan”. This was a more polished work compared to the previous game, and introduced a levelling mechanic to the gameplay. At this stage, Pixel also developed his first music tool and the minigame “Azarashi”.

Screenshot of Ikachan's WIP version

Cave Story Beta (Story and Characters)

Following the release of Ikachan, Pixel decided to work on Cave Story again. This version of the game, commonly called “Cave Story Beta” by the community, was in development from 2001 until late 2002.

What Cave Story looked like when Pixel resumed work on it

While not much is known about this version, we can get an idea of what it was like based on several screenshots and interviews.

Top-left: Curly Brace, Mimiga Sue, Unknown character, and Professor Booster

Top-right: The floating island (Mimiga Island?)

Bottom-left: Puu and Soa, the antagonists

Bottom-right: Professor Booster, Curly Brace, Momorin and Mimiga Sue

The game took place in a floating island in the sky (presumably what later became the “Mimiga Island”), and had as main characters the hero (back then named "Curly Brace"), the mimiga Sue (featuring a different design, with some tribal marks on her cheeks), "Professor Booster" and "Momorin". They are all seen in the screenshot above.

A character called "Puu" was the main villain of the story, and a recurrent boss. His design was based off of a bar of soap, and he would often wear things on his face (like scuba masks).

Puu was joined by smaller versions of him, called “Soa” (devired from the word “soap”), which Pixel refered to as “shocker enemies” (a reference to the basic enemies fought by Kamen Rider). Some burning enemies were also refered to as Soa.

Puu facing off Curly Brace


[Puu]: When the Mimiga are put in the water, they become easier to eat."


It's easy to imagine Puu was some sort of prototype version of the Balrog character from the final version of Cave Story. Their sprites are very similar, and just like Puu, Balrog also fights you several times throughout the course of the game. The boss “Pooh Black” in the final release of Cave Story is perhaps a nod to this early iteration of Balrog.

Pooh Black's sprite in Cave Story

The game also featured another villain, a cloud named “Oscar”, who could shoot lighting.

It's my personal assumption that Oscar's attacks were later inherited by Misery, as Oscar is nowhere to be seen in the official release, and Misery has lighting-based attacks. It's also interesting to point out that Pixel mentioned Misery did exist back in the Cave Story Beta days, but she was not an antagonist.

 It's mentioned by Pixel in his posts on the website 2ch that the Mimiga were enemies of the Soa (and Puu). The Mimiga were on the player's side, living a life based on growing flowers. He also mentioned their name derives from “Lop-eared Rabbit”.

An archived version of Pixel's posts on 2ch, dated way back to 2001. Right click to open it in a new page at the original size.

Explanation of the most relevant posts:

March 8th, 2001 (Boss screen): This boss encounter was called "Soa-Gravity". I believe this was the earliest version of Puu, as it did not even have a name yet, and it lacked his cheek marks. It's interesting to note that Balrog's theme in Cave Story is called "Gravity". Pixel mentions the boss was designed in the fashion of "Rockman" or "Milon's Secret Castle".

March 8th, 2001 (Chie screen): Pixel is saying the mugshots shown in the dialogue boxes help the player identify who is speaking. The Mimiga speaking here is called Chie, and that was her temporary name back then. It's interesting to note that, while she appears at the Plantation in the final release, her role is very minor.

July 16th, 2001 (Top-right screen): The comment on this screenshot mentions 'finding weapons that expand your movements possibilities...". There's a comparison to Ikachan made here, as in that game you could also find a special cap to destroy blocks. So, the Missile Launcher was possibly a weapon that you had to get in order to destroy a special type of block and access new areas. Pixel also mentions the flashy effects were inspired by Warano's "Tori game".


Among the Mimiga who appear in this Beta version, we can recognize Chie (who has her own mugshot) and her grandfather. Both are present in the final version of the game.

Chie saying "Sue is not here. She went to the mine”. Please correct me if that translation is wrong.

Perhaps most fascinating is the fact that the game had more than one playable character. Other than Curly Brace, you could also control Sue and a Frog Prince.

There are screenshots of an area marked by frog imagery in its tileset. Maybe you were supposed to visit a frog kingdom/cave at some point?

Frog-themed area

A frog enemy?

Cave Story Beta (gameplay)

In contrast to the previous Cave Story Alpha, this version had the familiar run-and-gun gameplay seen in the official release.

Still, some gameplay mechanics were different back then. Guns had limited ammo, forcing you to buy more ammo using money dropped from enemies (cion).

At the end of 2002, the gameplay of this beta version was further tweaked with the addition of the level-up mechanic from Ikachan.

In an interview, Pixel said the major reason for restarting the project was his insatisfaction with the game's level design and ideas, citing "shallow gameplay". It's worth noting that he made the game all the way up to the final boss battle, only to scrap it.

At the “Tokyo Culture Culture” event he also mentioned other reasons for scraping the game were the fact that the game was "big and confusing, and players got lost often." Apparently not many players liked the relationship between ammo and money, prefering unlimited ammo as it fit better the gameplay and was overall more fun.

Curly Brace fighting some Soa enemies to gather cion 

In Pixel's words: "at first I was thinking of a game that required careful bullet/ammunition management; take down enemies then use the collected money to obtain more ammunition. It was that type of game."

Dated February 20th, 2002. This NPC was often seen near a sign saying "ARMS". A shopkeeper for Ammo, maybe? It's hard to say. The items shown in this screenshot are your inventory items. Maybe the idea was that your inventory was opened and you picked a gun to recharge?

Among other changes, the game seemingly lacked any sort of vertical aiming. There are no screenshots featuring vertical aiming, so it can be assumed that feature didn't exist yet. The gameplay physics/movement were also different back then, and were later tweaked to ensure better gameplay.

A detail that caught my attention is that a cactus and a flower pot are always seen nearby each other. I assume these were the equivalents of the Floppy Disk / Health Stations seen in the final game. The only available video footage of the game shows the player spawning next to a cactus.

One can assume the work Pixel did between late 2002 and late 2004 (when Cave Story was officially released) was heavily based on assets he had already made up until then. While a portion of the content was effectively thrown away, some screenshots suggest many ideas were simple repurposed or rearranged to fit his new goals. 

The beta version had a wide variety of guns, just like the final release, perhaps even with the same gameplay functions.

The UI elements here are all pretty standard, except for the empty space under the "Weapon" slot. It says "Plug". Without any in-game context, it's hard to imagine what could go there. If you compare the equippable items in the final release of Cave Story, maybe you'd plug things like the Booster.

Blade-esque attack

Machinegun-esque bullets

Bubbler-esque bullets

Cave Story Beta ("First Cave" analysis + "Final Cave" analysis) 

Since there's only one available video footage of the game, it's impossible to know how the areas fit together and how the game progressed. Fortunately, at least the first area of the game seems to be documented to a degree.

I'm calling it "First Cave" because that's what the first area in the final release was called. Just for the sake of convenience.

A very simple room. The player has no ammo, very little health, and no gun.

This room's design is similar to the starting room in the final release, which leads me to believe this is the room you started the game in. As mentioned previously, the flower pot could very much be the equivalent of a save point.

Dated February 4th, 2001.

Still the same area as above, maybe just a few maps after starting the game. Curly Brace already has a gun (it might come loaded with 1000 bullets?) by this point.

This is a save point area, as seen in the video footage linked previously.

Based on the same footage, the player heads through an area called 暗い小道 (Dim Path) , fighting some basic Soa enemies along the way.

Boss Time! Based on the dialogue below, this is the first time the player encounters Puu.

This fight is very reminiscent of the second encounter against Balrog in Cave Story.

The map is called プーレストラン (Puu's Restaurant). The cutscene in this area is translated below:

[System Message]

宝箱をあけた>You opened a treasure box. 

100cion手に入れた>You got 100 cion.

ヤッホー>Yahoo! (Huzzah)
「プーのレストラン」に、ようこそー。>Welcome to Puu's restaurant.
さて、きょうのメニューは…>So, today's menu are...
あれ、おまえはミミガーじゃない?>What? You are not Mimiga?
んじゃ泡友達希望?>Then, do you want to be soap friends with me?
んなワケないよねー?>Nooo. Do you?
プー、オマエ知ってるよ>I know you.
コロシニ来たんでしょ?>Have you come here to kill me?



Dated February 4th, 2001.

This screenshot shows the "burning Soa" mentioned previously. This could be part of the "First Cave" area, judging by the tileset's colors and how the player has no weapon and very little health.

Dated July 17th, 2001. Just like the screenshot above, I think this is also a part of the first area.

This is a screenshot of what's likely to be the final boss of the game. It's been mentioned by Pixel that he actually completed the rough outline of this version up to the final boss, a confront against a bigger version of Puu.

Some interesting things to take note here: the location seems to be quite similar to where you fight Misery in the final release of the game, except it seems to be inside a cave. The falling blocks are also similar to an attack Misery uses, and similar to the escape sequence when the island starts falling apart. These ideas were present in this Beta version and made their way to the final release with some alterations, which is interesting.

Assorted Images

Some tools Pixel developed to make the game. These are dated late 2000.

Concept art for the Sand Zone, maybe?

Concept art for the Core boss

Various unused sprites, some found in the game's folders

A "Cave Story 10th Anniversary" picture posted by Pixel. This is by far the most interesting picture, in my opinion, as it shows how the game progressed all the way from July 6th 1999 to December 20th 2004.

Due to the work-in-progress nature of this page, I haven't included every image I have yet.


Potential Inspirations / Homages

Metal Slug

The Machinegun weapon in Metal Slug games behaves and looks very similar to Curly's Machine Gun.

Super Metroid

First we have the Health Capsules and Missile upgrades that are very standard to Metroid games.

The Snake weapon in Cave Story also functions just like Metroid's Wave Beam, phasing through solid walls in a sine-wave pattern.

Lastly, and this one is the most curious to me, is the similarity between the Dragon enemies from Super Metroid and the fish enemies in the Plantation area. Their positioning and behavior are alike. 







Sources 168541.phtml

Pixel's BBS

2ch (


-rdein (October 2016)