Save File Format

typedef struct {
    u16 quest_unlock_index;         // +0x000
    u16 quest_unlock_index_full;    // +0x002
    u32 weapon_usage_counts[53];    // +0x004
    u32 quest_play_counts[91];      // +0x0d8
    u32 mode_play_survival;         // +0x244
    u32 mode_play_rush;             // +0x248
    u32 mode_play_typo;             // +0x24c
    u32 mode_play_other;            // +0x250
    u32 game_sequence_id;           // +0x254
    u8 reserved[0x10];              // +0x258
} game_status_t;  // 0x268 bytes

// File layout:
// [0x000..0x268): Obfuscated payload
// [0x268..0x26c): Checksum (u32 little-endian)

def obfuscate_byte(plaintext: int, index: int) -> int:
    """Obfuscate a single byte."""
    i8 = (index & 0xff) if index < 128 else (index & 0xff) - 256  # Signed wrap
    poly = ((i8 * 7 + 0x0f) * i8 + 0x03) * i8
    return (plaintext + poly + 0x6f) & 0xff

def deobfuscate_byte(ciphertext: int, index: int) -> int:
    """Deobfuscate a single byte."""
    i8 = (index & 0xff) if index < 128 else (index & 0xff) - 256
    poly = ((i8 * 7 + 0x0f) * i8 + 0x03) * i8
    return (ciphertext - 0x6f - poly) & 0xff

def deobfuscate_payload(data: bytes) -> bytes:
    return bytes(deobfuscate_byte(b, i) for i, b in enumerate(data))

def compute_checksum(decoded: bytes) -> int:
    """Compute 32-bit checksum of decoded payload."""
    acc = 0
    u = 0
    
    for i, byte in enumerate(decoded):
        c = byte if byte < 128 else byte - 256  # Signed wrap
        acc = (acc + 0x0d + ((c * 7 + i) * c + u)) & 0xffffffff
        u = (u + 0x6f) & 0xffffffff
    
    return acc

import struct
from pathlib import Path

class GameStatus:
    def __init__(self, file_data: bytes):
        if len(file_data) != 0x26c:
            raise ValueError(f"Invalid save size: {len(file_data)}")
        
        # Split payload and checksum
        obfuscated = file_data[:0x268]
        stored_checksum = struct.unpack("<I", file_data[0x268:0x26c])[0]
        
        # Deobfuscate
        self.decoded = deobfuscate_payload(obfuscated)
        
        # Validate checksum
        calculated = compute_checksum(self.decoded)
        if calculated != stored_checksum:
            raise ValueError(f"Checksum mismatch: {calculated:08x} != {stored_checksum:08x}")
    
    def get_u16(self, offset: int) -> int:
        return struct.unpack_from("<H", self.decoded, offset)[0]
    
    def get_u32(self, offset: int) -> int:
        return struct.unpack_from("<I", self.decoded, offset)[0]
    
    @property
    def quest_unlock_full(self) -> int:
        return self.get_u16(0x002)
    
    def get_weapon_usage(self, weapon_id: int) -> int:
        """Get usage count for weapon ID (1-52)."""
        if not (1 <= weapon_id <= 52):
            raise ValueError(f"Invalid weapon ID: {weapon_id}")
        return self.get_u32(0x004 + weapon_id * 4)
    
    def get_quest_plays(self, major: int, minor: int) -> int:
        """Get play count for quest major-minor."""
        index = major * 10 + minor
        if not (0 <= index < 91):
            raise ValueError(f"Invalid quest index: {major}-{minor}")
        return self.get_u32(0x0d8 + index * 4)
    
    @property
    def survival_plays(self) -> int:
        return self.get_u32(0x244)

# Usage:
save = GameStatus(Path("game.cfg").read_bytes())
print(f"Quests unlocked: {save.quest_unlock_full}")
print(f"Pistol usage: {save.get_weapon_usage(1)}")
print(f"Quest 3-5 plays: {save.get_quest_plays(3, 5)}")
print(f"Survival plays: {save.survival_plays}")

# View save file
uv run scripts/save_status.py info game.cfg

# Unlock all quests
uv run scripts/save_status.py set game.cfg --set quest_unlock_index_full=90

# Set weapon usage
uv run scripts/save_status.py set game.cfg --set weapon_usage.1=100

# Set quest play count
uv run scripts/save_status.py set game.cfg --set quest_play.35=50

Offset  Hex                                           Note
------  -----------------------------------------    -----
0x000   6f d0 9a 05 ...                              Obfuscated payload
0x268   4a 3c 8f 12                                  Checksum (u32)

Offset  Hex                                           ASCII
------  -----------------------------------------    -----
0x000   1e 00 1e 00                                  ..  (quest_unlock=30)
0x004   00 00 00 00 0c 00 00 00 ...                  ... (weapon usage)
0x0d8   02 00 00 00 01 00 00 00 ...                  ... (quest plays)
0x244   0f 00 00 00                                  ... (survival_plays=15)