The difficulty of mobs can be categorized in “Difficulty by numbers†and “Difficulty by strengthâ€
Bosses are the latter. Most trash mobs the former. Imagine how boring it would be to always only meet 1 strong mob at the time. Often it’s harder to meet multiple enemies because you need to make decisions on which mob to take out first (or if you’re smart use AoE
)
Anyway, I don’t think you can judge too much from the demo. I mean the first levels are supposed to be easy even for people unknown to the genre and on top of that choose a totally stupid talent path. So quite obviously it’s easy for hardcore players who know what talents to pick. ^_^