First of Many - Die for the first time
I think this one is self explanatory. Just become dead. Easiest way to do this is to use an app on the computer so time starts zooming by until you fall asleep. Do it again and you'll be dead.

What's the Point - Halfway
Acquire 8 postcards. A postcard is acquired each time you die.

Goodbye - goodbye.
Acquire all 16 postcards, then die again and talk to the cat for the last time. You have to get each postcard individually (by dying 16 times in a row) and have the cat in each one. If the cat gives you all the postcards at once, then he will disappear from the postcards, and you'll need to reset your game in order to get this achievement.

Destined to Die - the end.
Beat the game by making it past the rainy day alive.

Water Rain - Water Rain?
Make it to the rainy day alive. I think day 9 is the rainy day.

Single gang? - being single is fine...
Apparently you need to beat the game without talking to any physical humans.

I suggest this guide, it's a lot better than mine: https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2651054492