I believe there were some updates in the last few years because there are clear signs when you enter the UNESCO area as well as maps to explain which area are the UNESCO area. Knowing this you don't waste your time exploring the northern playground part and go directly to the area you want. I saw NORTH because that's what the maps shows but Singapore has the tendandency to show a map with north going not up so I don't actually know.

Most of the park is free aside from the Orchid Garden which costs a small fee. It's definitely worth seeing the orchids. The outside one have blatantly been planted but the greenhouse alone is worth seeing. You should also go through it twice just to enjoy the lovely flowers. The rest of the botanical garden is rather meh.

There are lizards, turtles, birds, many plants and treees, you won't be disappointed really. There are also temp special exhibitions that don't really related the the world heritage such as fig plants (it keeps changing, I think figs was 2024). It's good to be in an air-conditioned section though.

On my second visit I wanted to see parts of the gardens I hadn't visited before but during the day this doesn't seem to be special. I think at night the frogs, spiders, bats?, even snakes come out. At last when it gets darker. The entire "rainforest" section was empty during the day although I still preferred that over a paved road in the sun. I find it shocking that a small forest alone can house all these animals and I sometimes don't believe it. On Sentosa you get similar signs about snakes etc but I started not to be worried about anything. It would be good to talk to an environmental expert at the park to get an idea how many flora and fauna are really here.

The metro station takes you right to the entrance  and if you have a few hours then definitely go and check it out. Don't go on a Sunday when the maids picnic over the entire park.