Creating Assets
PCX Images
Use GrafX2 the DOS pixel art editor (Windows/Linux/Mac):
Draw with 256 colors (any resolution supported)
Save as PCX format (RLE-compressed)
Common sizes: 320×200 (full screen), 32×32 (sprites), 16×16 (tiles)
VOC Sound Effects
Use Audacity (Windows/Linux/Mac):
Import audio (WAV, MP3, etc.)
Tracks → Mix → Mix Stereo Down to Mono
Tracks → Resample → 11025 Hz (or 22050 Hz)
File → Export → Export Audio
Format: “Other uncompressed files”
Header: “VOC (Creative Labs)”
Encoding: “Unsigned 8-bit PCM”
HSC Music
Use one of the following:
Adlib Tracker II - More modern approach (Windows/Linux)
HSC-tracker - The original HSC tracker (only DOS)
TMX tilemaps
Use Tiled a full-featured level editor (Windows/Linux/Mac). See the restrictions at the tilemap documentation.