I forgot to put in a second hint today since this one hadn't been guessed yet. Let's see if someone's quick enough, I'll post it in a few hours.
#30: In the early days of this franchise, it seemed like every game was some sort of a 'subgame' of the famous 'main game'. Every game is still a full blown game though, and mine in particular focussed on one single building.
#30 (Hint 2): A tall building to be exact, and on top, on the 100th floor, you'll finish it by building the great Cathedral as it's crown.