Total War: Warhammer III was announced some months ago, but no public footage has been seen beyond a few teasers. But now you can watch a lengthy 30 minute gamplay demonstration in all it's glory. Being shown off is a new excursion segment into the chaos realms and some new factions.
Purveyors of Total War on Mac Feral Interactive has already promised they will be be porting the game to Mac & Linux and it should be available shortly after the PC launch. You can pre-purchase the game on Steam.
See the WH3 FAQ for more info.