Which is the recommend difficult setting for Europa Barbarorum?
Europa Barbarorum is best played on Very Hard / Medium. The AI is aggressive (in particular the slave faction) but dont get stat bonuses on the battlefield. If you want a real challenge try VH/VH but be aware enemy units on the battlefield are getting massive bonuses (afaik: +7 attack, +7 defence, and a huge morale boost), you could have your fullstack army is hacked to pieces by 5 units levies…
