I dragged the kids there on our rest and relax day in Siem Reap. I say drag because we walked 40 minutes in the rain before we found it (it was 5 minutes by tuktuk on our return leg, we stayed at Golden Temple Hotel). It is a bit away from the Pub Street Area but check a map, it's not hard to find.
As we were there on a rainy Monday afternoon, we were the only ones there! This was not too fun for the kids since they had no one else to play with but I can't complain since service was quick.
After lunch (standard western kid's fare - fries, pizza, pasta, floats), we got to pick a movie and watch it, just the 3 of us, in their own private cinema with free (unfortunately tasteless) popcorn thrown in. Loved it, my favourite part! Be warned that the seats are kids' size and I barely squeezed into one.
There is an indoor playground and a large outside area with sandpit, bouncy castle, trampoline etc. Did not explore much outside due to rain.
Would definitely love to come back again. It's one of those places you can let your kids run around whilst you read a book and have a couple of beers. Lovely.