Thanks for the report!
This crash happens if you load an old save after updating to v0.2.0. It’s expected for now. Starting a new game with 0.2.0 should work fine.
The mod is under active development and I’m still stabilizing the core mechanics. Because of that, I can’t guarantee backward compatibility yet — adding migrations at this stage would slow development too much. Once the core is stable, I’ll support save upgrades.
If you want to keep your current run, please use the previous version. If you want to start a new run and test the mod, you can use 0.2.0