I bought it without doing the demo. Yes, it is a bit more difficult but I like it for the challenge, as well as the instant blank-space fill in that I mentioned with Fantasy Mosaics 2. I've just about all the grinder or similar puzzles that BFG has offered. Yes, they get nasty hard. I've had some games on my pc for a while now bcs I want the gold, silver just isn't good enough for me. Yes, it takes some memorizing to get them done; good for the brain. Fact is, I'm ready to get back to the current puzzle right now - see ya!