Come on weekdays and even on weekends. The front staff is very helpful, and exchanging tickets purchased through Traveloka is very easy. For those who don't have a Game Master card, you need to get one first. For security, it's best to use a locker. A 10,000 IDR deposit is required at the end, which you'll need to return as long as you don't lose the key.
There are quite a lot of rides, safe for children aged 3+. Oh yeah, one ticket is for one child and one guardian. Children under 1 year old are free if an older sibling is playing. Both guardians and children must wear socks, preferably with elastic at the bottom, as they can be slippery.
Play as much as you like, and don't forget to exchange your wristband at the exit when you're done.