Yes, a few years ago the aquarium broke away from the Maritime Silk Route theme to include habitats from other regions such as the Caribbean and Australia. Since then there hasn't been much of a coherent theme for the aquarium as a whole. Last year, the maritime museum was turned into a separately-ticketed attraction and is no longer part of the aquarium route. In the years to come, the maritime museum will make way for the aquarium's expansion.
I'll second this: Don't try to squeeze in the Night Safari after a full day at the other parks. It's much more enjoyable when you're fresh faced.
A few thoughts: I think the zoo isn't a true contender for best in the world, but it is one of the true Greats of the international scene and has a name recognition amongst the general public that few could match. It's also worth pointing out that its highlights are world-beating, it's just that they aren't representative of the zoo as a whole. I've done three trips to SG, the first time I did all five main collections, the second was a rushed visit that only had time for a revisit to Jurong, and the third time I did Jurong and the Zoo again. I thought the Zoo did surprisingly well on a return visit, I think I had over-emphasised its weaknesses in my head and I thoroughly enjoyed my day there. I will quote myself here for thoughts on Jurong: I think sadly the true challenge for Jurong is that Walsrode exists and so those of us who have visited both can't help but know how much more Jurong could be, especially on the current site. River Safari: Just a bit of a disaster sadly. The boat ride is very bad as almost everyone has pointed out. I like the manatee pool and the freshwater aquarium section. The panda exhibit is totally out of place, but as @CGSwans once pointed out it's probably the only thing that makes the River Safari financially viable. I think once the new parks are open WRS will need to take a serious look here and sort a lot of stuff out. (However, given that the Rainforest Park will focus on Southeast Asia I imagine a greater priority will be to rework the Zoo with a greater focus on Africa, as unless they double-up on lots of species I guess plenty of the Zoo's Asian animals will move over.) My visit to the Night Safari was one of my best zoo visits of all time, so much so that I have avoided revisiting in case it turns out to not be as good as I remember. As @lintworm says there's something quite magical about seeing animals at night. it definitely suffers from the Singapore syndrome of small enclosures for large mammals but otherwise was simply glorious. SEA is very good IMO, but it lacks 'heart' or whatever makes a place special. Also, the main tank is substantially deteriorated by the hotel windows you can see opposite the main viewing window. My own advice would be to do the Zoo as a single day visit, and then on a different day visit the River Safari in the afternoon and the Nigh Safari in the evening. I find that to be a much better way of managing heat and fatigue, but each to their own of course. I hope and plan to visit next year for a final look at Jurong (still haven't seen Spix's and Lear's), and this time I'll probably make the effort to revisit all five collections. Then of course I'll have to that all over again once the new stuff is open.....
