So far what ive learned playing Impossible Minecraft is:
1. Its weirdly calm once you get settled in
2. Never take more than the extremely bare essentials
3. Mob path finding is atrocious, the impossible mobs are no exception, anything that stops them from "finding" ya is crucial
4. Bamboo is a good defense so long as ya plant it well, no block un-planted, mobs cant spawn or follow you but you can walk on through
5. Placing blocks so you can see farmland but farmland can't see you keeps the scarecrow away (bamboo tested, not sure bout slabs and trapdoors yet)
6. Sharks dont spawn with waterlogged blocks, fire cant get ya if you're wet, combine the 2 concepts for safe furnace use
7. Kelp and Bubble Columns don't seem to spawn any sharks, a whole sea o them should be safe to swim in
8. Melons are friends in the beginning, plant once and they can be harvested without scarecrow nonsense
9. Spiders are still friendly during the day but will web ya if you get too close, good for string, make sure to jump for 2 webs
10. For the builders, use a bed to avoid trees shedding their bark, the leaves might safely catch ya but still be wary of fall damage
11. As scary as sharks are they can only outswim and not outrun, build bridges across the ocean in the water as opposed to above it, that way you can jump back up if you fall
12. A fishing rod can fish items out of the water for you
If anyone else is playing the datapack and has more tips and tricks lemme know so I can add em to the list. I very much like not dying so any help would be appreciated :D