If you're not familiar with Cave Story, you should be. It's a fantastic game! This page deals specifically with the original free-as-in-beer version of the game, and even more specifically to the Linux port of that version (though I think it would apply to at least any of the PC versions of the game). It does not apply to the newer Cave Story+ versions, nor to to the versions released by Nintendo onto the Wii or other of those platforms. Still, if you've still got a copy of the original game lying around, read on!

Sacred Ground Savefiles

Anyway, a little while ago I wanted to go see what it was like going through Sacred Ground using the various weapon choices that you've got available, and found that, apart from the boss battles, the game does get rather dull once you've played it through a couple of times. Figuring that others could possibly benefit from the fruits of my labour, though, I figured I'd throw up a set of savegames from just before entering Sacred Ground. All of these savegames feature full health, full missiles, and the Life Pot (and, of course, the Nikumaru Counter). The Snake and Spur savegames are missing Chaco's Lipstick, unfortunately, though the Polar Star and Machine Gun saves do have that item as well. As far as I know, that's the only thing missing from any of the savegames.

To use these, save them as "Profile.dat" in your Cave Story folder. Note that this'll overwrite whatever your current savegame is, so make backups if that bothers you. I should also point out that these savegames were created using the Linux version of the game. I'm guessing that they're compatible with the savegames from other platforms as well, but I can't be 100% positive about that.

Polar Star (heh)
Machine Gun
(Click the images to download the savefiles)

Savegame Format

Shortly after collecting those, I got curious about the savegame format, too, and I took a little bit of time to figure out a bit of the syntax. If you feel like hacking on a savegame to give yourself some different weapons, etc, this could save you a few minutes.

I actually also put together a little "cheating" savegame, if anyone's interested, which will start you out at the very beginning of the game with the following: Spur, Snake, Machine Gun, Blade, Super Missile (with 30 missiles), 50 health, the Arms Barrier, Turbocharge, Booster v2.0, and Whimsical Star. You can download that one here: cheating.dat. Enjoy! Disclaimer: I have no idea how this will end up interacting with the rest of the game, down the line. I only played it pretty briefly. It was pretty fun just storming through the Egg Chamber, though.

When I say "short" I mean an integer that's two bytes long. When I say "int" I mean an integer that's four bytes long. It's also worth noting that for weapon slots and inventory, the game will apparently just continue to load in weapons/items until it gets a zero for the weapon/item type. While playing around with stuff, I was able to actually give myself all weapons at the same time, and have enough items to start overwriting bits of the screen that they're not really supposed to. I don't recommend doing that. For instance, If you give yourself at least nine weapons, the ninth weapon slot actually overlaps the first inventory slot in the file (the file is fixed-length), so if you give yourself a ninth weapon of the Bubbler, that'll suddenly make the ID Card appear in your inventory. As the weapon changes in level, etc, your inventory slots will keep changing as well. I'm not sure if anything else is used inbetween the fifth weapon slot and the beginning of the inventory, so you'd best just stick with five.

(Note too that it's possible my Cheating savegame could cause problems. For instance, you can still go pick up the Polar Star right at the beginning, and it'll be added as a sixth weapon. It's possible that doing so is inadvertantly setting some other game flags which could have strange results later in the game.)

(Also note that this is clearly not the entire file. This is just as far as I got before losing interest. I can't think of anything else I'd really want to be able to modify in a savegame, anyway.)

0x1C short Maximum Health
0x1E short Whimsical Stars currently active (zero through three)
0x20 short Current Health
0x38 5 ints First Weapon Slot

Each weapon slot takes up five ints, for a total of twenty bytes.

1Weapon ID
2Weapon Level (1, 2, or 3)
3Extra Energy (towards next level - will result in graphical glitches if you go higher than the weapon's max for its current level)
4Maximum Ammo
5Current Ammo
Max Energy per Level
Weapon IDWeaponLevel 1Level 2Level 3
0x02Polar Star102010
0x04Machine Gun304010
0x05Missile Launcher102010
0x0ASuper Missile306010
0x4C 5 ints Second Weapon Slot (see above)
0x60 5 ints Third Weapon Slot (see above)
0x74 5 ints Fourth Weapon Slot (see above)
0x88 5 ints Fifth Weapon Slot (see above)
0xD8 int First Inventory Slot

Inventory seems to be just a string of integers. Inventory has six columns, and four or five rows (see above for why I'm not sure what the actual limit is). Note that merely having an item like Booster v2.0 or Whimsical Star doesn't automatically make it active (even though I don't think Whimsical Star needs to be activated when you get it during the actual game). Arms Barrier and Tubocharge seem to be automatically active if they're in your inventory, though. Go figure.

0x01Arthur's Key
0x02Map System
0x03Santa's Key
0x04Silver Locket
0x05Beast Fang (?)
0x06Life Capsule
0x07ID Card
0x08Jellyfish Juice
0x09Rusty Key
0x0AGum Key
0x0BGum Base
0x0FLife Pot
0x11Clinic Key
0x12Booster v0.8
0x13Arms Barrier
0x15Curly's Air Tank
0x16Nikumaru Counter
0x17Booster v2.0
0x18Mimiga Mask
0x19Teleporter Room Key
0x1ASue's Letter
0x1CBroken Sprinkler
0x1ETow Rope
0x1FClay Figure Medal
0x20Little Man
0x21Mushroom Badge
0x22Ma Pignon
0x23Curly's Underwear
0x24Alien Medal
0x25Chaco's Lipstick
0x26Whimsical Star
0x27Iron Bond

That's about it for now, I think!

Let me know if you've got questions, comments, or barrels of money you'd like to send my way.