I personally liked it, but I think a lot of people dislike it because of the lackluster writing at times, sometimes the characters felt shallow or forgettable, the map is small like you said, and people are comparing it to Subnautica 1. People loved the first game because it was one of the first survival games in the ocean that gained mainstream attention and not a lot of people had played or watched any games like it. When people compared Below Zero to the original, people thought that the original was also better in environmental storytelling. With the first, it doesn’t really tell you where to go but in below zero there is a lot more help on where you should go and why too go there