Seas of Blood… this is going to be a tough discussion for me, because I have to admit this was the gamebook which I read/played more often than any other when I was a kid. Whether this was due to thematic preference, due to gameplay-related strengths or other aspects, we will probably find out. However, I cannot guarantee that I can stay objective at all times. Please excuse the occasional drift into nostalgia.
Imagine the beginning of a great adventure: You are standing in a forest. The sky is blue, the sun is shining and the wildlife is wandering about. There is a guy named Jack, Steve or Brat next to you, who will turn out to be an invaluable source of information, for he is The Guide. With great foresight you brought a set of tools along, so you can start right away. What will it be? Do you want to start digging, to search for valuable ores and treasure caves? Or do you want to attack that slime creature that is coming closer, in the hope that it will drop some valuables? Or how about building a base, maybe a log cabin, first? All of this is possible in Terraria, an open-world 2D platformer, that combines the fun of exploration, fighting and building in one game.
Steampunk. What started as an original and not entirely unfascinating thought experiment has by now been reduced to stupid costumes primarily consisting of top hat plus welding goggles. It's hard to imagine why a new game would jump on that sad train in 2016. What is even more surprising, however, is that this game then actually doesn't use its self-proclaimed theme after all. Mysterious.
Steam Sky is probably best described as a turn-based Elite. Not that it takes place in space. The player navigates between floating air-bases. In a ship which is probably running on steam and consists of parts whose names don't give the impression that such weight could ever fly. Though that is the whole idea of steampunk, isn't it? That's it thematically, though.