Singapore is sadly lacking in fun restaruants for kids. Back in the UK we used to have lots of them, where you have a drink while the kids go off for an hour or so of play before eating. They were great for rainly days.
This could be a good business opportunity in Singapore!
But back to the topic, the only places I can think of (other than the ones mentioned) are the Fisherman's village at Pasir Ris - which is on the beach and there's a big kids playground behind it, but not actually attached to the restaurants, so you'd have to keep going around there to keep an eye on them. Or there's Pasta Fresca down at the East Coast Park which has got a slide and climbing frame, but sadly it's set apart from the main eating area - however my kids like to go down there and play on the beach and paddle (make sure you take wet wipes so you don't have to keep going to the toilets to wash sandy hands before eating!). These places are all outside though, so not much good in wet weather.
There's an indoor kids play area at the NTUC centre at Pasir Ris too, but it's not actually attached to a restaurant, although there are restaurants around there.
Hope this helps - most restaurants here are very kid friendly though and they don't seem to mind them running around a bit (NOT like back home!!!)
