📄️ PAK files
PAK files are checksum-verified packages that contain a full filesystem structure inside them - they store all assets for the game. PAK files can be layered on top of each other - the game will first search for res.pak, then res1.pak, then res2.pak (etc.) while loading PAKs - PAKs are incrementally stacked on top of each other during the loading process - conflicts are ignored, and the PAK with the highest priority is used.
📄️ HashLink bytecode (and hlboot.dat)
Based on the documentation at the excellent hlbc wiki, and improved with information from the development of crashlink.
📄️ Save Files
This is Dead Cells' specific binary save file format. It stores multiple serialised objects in a compressed format along with hashes to prevent corruption or tampering.
📄️ hxbit/HXS Data (Save file payloads)
HxBit is a binary serialization and network synchronization library for the Haxe programming language. The corresponding file format, often with an .hxs extension, is designed for speed and efficiency, using a compact binary representation instead of a more verbose text-based format. This makes it ideal for applications requiring fast loading times and a small data footprint, such as games and networked applications.