In order for you to play Bridge Constructor Medieval on Linux with minimal graphics settings, your computer must meet the following requirements
Operating System:
Ubuntu 12.04 or equivalent (32bit or 64bit with ia32-libs installed)
Processor (CPU):
1,8 GHz
Memory (RAM):
1 GB RAM
Graphics Card:
Linux 64bit users need to have ia32-libs package installed (sudo apt get install ia32-libs)