This zoo is huge. It's usefully separated into continents and you are given a free map at the ticket desk so finding your way around is relatively easy. Given the size and layout, I would recommend planning your route carefully at the beginning of your visit. The size was not a problem for us. However, if you are with small children it might be worth considering skipping some areas. I noticed that the zoo did provide parents with pushchairs, although it also seemed as if alot of the children were very tierd. There are plenty of cafes, children's play areas, shops and toilets around the zoo. Leave alot of time for your visit so you are not rushing, even without children or elderly people you will need a couple of breaks.
Staff are very friendly and happy to speak english.
The zoo has all the animals you would expect. We were lucky enough to vist at a time when there were lots of new baby animals, which was a bonus. The zoo website lists recent births, so that might be worth checking before your visit. I was particularly excited to see the polar bears. However, I was a little disappointed. Whilst I'm sure the zoo looks after the animals the the level required by law, the polar bears seemed sad. Their enclosure was just a field with a small pond. On the other hand, most of the animals seemed fine. The seals are particularly worth a visit, and there is a large butterfly enclosure.
The atmosphere of the zoo was very disappointing. I visited Amsterdam Artis Zoo a few months ago and it had lovely food and beautiful gardens. Rotterdam Zoo, on the other hand, was slightly unpleasant. The food is okay and reasonably priced, but not particularly enjoyable. Everything is a little bit dirty. The walk to the zoo is along a busy road. Worst of all, the zoo is built around a train track, with half the zoo on one side and half on the other. I'm not sure how disturbing this is to the animals, but it is not pleasant for visitors.
Overall, I would give this zoo 6 out of 10. It is functional and reasonably priced, but quite unattractive. I would strongly recommend visiting Artis instead.