I did some quick test in fire starter area, comments:
1. I love that the upgrade button is separate from the Quests 8)
2. "Fire bug" NPC has the right difficulty for the area, but it contains an upgraded Tower-shield which is unexpected for such low level deck -- I think upgraded cards should be used only in higher level decks
3. "Graviton Fire Eater" NPC is a bit too hard for a starter opponent IMHO, it has Unstable Gas -- devastating against low HP fire critters, CC, good-shield (wings).
4. After a few battles (and shopping in bazaar) you get the Quest: clear the area, kill everything in an area. However, new NPCs keep popping up after each battle, so it seems like an impossible challenge: kill 1 => 3 new pops up.
5. The idea of many NPCs suggested a more varied experience, i.e. that you don't have to keep fighting the same opponents decks over and over again. But with the current setup where you have multiple copies of nly 2 NPCs per area, the result is actually the opposite. A new player will keep facing the same opponent even more often than in v1.321