I've just played some 5-6 hours without login.
I reached lvl 12, so I collected a lot of Viagra (+40% Hero potion) and gems.
I climbed up to the 8th floor in the Tower. I have 41 cards, including a lvl 6 Navigator (for 500 gems), and 10 toys (common and rare).
I also won a few levels against the Bosses. The light is easy, I defeated it 10 times, so I won 4 boxes to choose one of the 10 girls... so I also have a few abilities for now.
The Colosseum is still hard with these cards, so the 10th floor limit is a good idea. I was also struggling with the water dungeon.
Of course I know what to collect. Still it is a way easier for beginners, and also more interesting.