It's actually interesting how difficult the early game is. If you want to buy the presents before Eric does you gotta plan out every step of that first week.
After that there is still a failure state, but you have to try to trigger it. There is still a hint of a game, but it's pretty easy unless you are trying to get that blackmail material on Eric (a holdover from the original game?). Then the gameplay element is dropped entirely and it's 100% grindfest that you can't lose. IMHO it would be more exciting if there was a chance for gameover every time you boned Lisa while your mom was home. Maybe with a sidequest where you can get her drunk so she sleeps more soundly.