I was looking forward to this pack more than I have any others, and so far, I just LOVE it! I love the way the sims move through the portals - no loading screen, but it does take a few seconds for them to get to the "other side". Its's a beautiful world, and because they can move around through the portals without loading screens, they can be in really different places while you're still able to move between them and control them both. There are loading screens for the specific lots, like the museum and the baths and marketplace, etc. But all the space (jungle) between those lots is like open world, so you can have them exploring in different places and still move back and forth between them.
The encounters with eggs, bats, sloths, etc aren't what I expected. I'd skilled my sims up a little - one in logic and rocket science, another in charisma and herbalism. I didn't realize that the encounters with the different objects were within the chance cards that you get when you go through a portal. So, the sim that is skilled in rocket science wasn't the sim that got the chance card about the egg. I thought I would be able to choose which sim would, say, pick up the egg or scare off the bats or walk through the sloths - but that's not how that works.
My sim got attacked by bees and did not have the flower she needed to ward them off, so got stung pretty severely. Fortunately, her husband had brought along a Soothing Skin Balm he made with his herbalism skill. She used that and the negative bee sting moodlet disappeared completely. WIN!
My sims spent the first two days in Selvadorado chatting up the locals and buying items from the vendors. They learned some good information, but despite several attempts, never got the chance to purchase some of the items needed in the jungle. Nothing has really threatened their lives yet, but if it's hard to get some of the items, that could get frustrating.