Altough a lot of the combat is about clicking at the right time, you will also have to rely on your magical powers. Using the right power at the right time can you save you a lot of trouble. You also got potions to help you out, but that's just a minor part of combat.
I don't know how the combat evolves later in the game, but I've played till I had all the powers (I think there were 4 or 5 different 'Signs'), it wasn't the combat system which made me quit though, as mentioned before it were the loading times that annoyed me, I love everything else about the game though(well an inventory that was a little more easier to manage would have been great, but it's doable as it is now).

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