Are the entrance tickets to Legoland park limited to a specific date?

Even though the ticket/voucher has dates, these dates are following the dates for your booked accommodation), you can choose which of the days you want to go into the park.
If you have booked a 2-day ticket to Legoland, you must enter on two consecutive days. (If the park is closed a weekday, you can go to the park the day before the closed day, and the day after.)