Having tried several games, the luck of the draw seems to determine everything. If I get early builders etc., I win easily; if the computer gets twice as many (more often the case), I have no chance.
Amusing, but a lot of luck. My first "beginner" game against the computer, it got about a dozen of the school/sorcerer/knight cards before I got two. That was not something I could overcome.
If you think the game is about luck or randomness, you are probably missing the point of the game. I can accept that after level 10, some of the levels might be impossible due to unhappy randomization in the colors (combined with fewer turns), but you should be able to get quite a ways with good planning. If you hit colors at random, yes, your success is random. If you are thinking even a few moves ahead, you can deal with a very fragmented board.