I think I'll talk about two similar games in this post: Salt and Stranded Deep. Stranded Deep is basically a Castaway simulator with relatively realistic graphics of islands and sea life. Salt is a more cartoonish island-exploring game where your main enemy is the pirates that pepper various islands.
But both involve gather rocks and sticks, crafting tools, acquiring food, and exploring infinite islands. These games focus more on the exploration part of a sandbox game than some of the others on my list, and island hopping is a really good way to do that.
I think the strong point of Salt is that the islands you find can be quite different. Some have pirate encampments, some ancient ruins. I found an ancient altar once, and have found merchants that traded with me and gave me a simple quest. I've hunted black deer at sunset and had a few terrifying nights fighting spiders by torchlight.
While you can build better boats as you get more materials and the books that teach you how to build them, one thing I found myself craving was the ability to make a change in the world-- to build a house or somehow make an island mine. But the world is not a voxel world, and when I last played the only things you could build on land where a campfire and a flag.
The worst thing about Salt for me was the poor quality of the art work for the pirates and the item icons in the UI. I realize the game is still in development and that you might want to put some placeholder artwork in a game you are making, but if your main enemy is going to be pirates I think you need to find artist to make you a better representation, even if a cartoony one. The item icons are small and cartoony and I would often have a hard time distinguishing them.
It is really cool to be able to dive into a shipwreck and find random loot in them. After a while you know all the possible items you can find in this game, but more items could be added- the point is that this setup scratches a fundamental exploration/scavenging itch I have. It's also neat to be paddling along and see a marlin, a sea turtle, or a great white shark. There are whales and sea urchins and sting rays too.
One of the things that get's frustrating is dealing with your limited inventory. I think this is another common way some of these 8 games try to make themselves more difficult and more "realistic" than minecraft by limiting how much you can carry. But when you have to go from island to island with sharks trying to bump you off your shaky raft carrying your precious bundle of sticks, rocks, and palm fronds, it can get irritating. I wonder why I can't make a raft of logs and then break it up at another island, or at least tie a bundle of fronds or sticks to my raft.
Another thing that bugged me was the way the game renders distant islands. Islands in your peripheral vision zoom closer and then zoom back out when you look directly at them. It makes it quite disorienting when trying to judge which island is closest and which you were trying to reach before the sharks attacked you and you lost your line of sight.
But I'd say the most disappointing thing is the homogeneity of the islands. Yes, they have interesting assortments of wrecks around them, but once you've seen one of the islands you've seen them all. The game really needs some islands that are bigger, with hills, waterfalls, and caves. The latest update to the game introduced Sea Forts and I've heard they might be trying to add caves, so that's cool.