I got the 80% discount code via email and it worked fine for me. Just had to enter the code first and select the version (Regular or Premium) to redeem.
Games looks great and seems to have a lot of potential, but most/all of the mechanics are incredibly cumbersome and hard to use. Manual combat is absurdly slow and time-consuming, trade routes will get stuck and convoys will just sit in towns doing nothing, tasks/quests are poorly described so you often have to search a huge area manually.
