When I die near the beginning of the game I get the following error:
Error while running event Underground Indicators::on_tick (ID 0)
Underground Indicators/control.lua:252: attempt to index local 'stack' (a nil value)
version: 0.16.7 tested without any other mods active.
edit: It was in multiplayer game but I was only person on the server.

Thanks for the report! I would fix this right away, but due to it being Christmas and all I expect to not have the fix up until tomorrow.

Merry Christmas!

I've uploaded v1.0.4 that should fix this issue. Let me know if you run into anything else!