The whole game was so peaceful, charming and amazing. Walking around was so serene and the environment was so vibrant! Even the storyw as pretty good and become quite emotinoal towards the end and such a bitter sweet ending. The way the music was used as well. especially towards the end; it was perfect.
Only things i could suggest is to maybe have the bot that the player finds at the beginning to follow you for a distance and maybe then stop functioning as it runs out of fuel or something like that. Making the players interact witht he bot more would make an emotional connection and tie that part up better. And there were probably astronaut parts around, but keeping them in the actual path to the triangles would encourage more exploration in the maps to find more of the pieces; and adding a story to each piece you find of the previous astronauts would also add a depth to the story.
The above is just a suggestion, the game is great just as it is and it was honestly really fun and great to play and experiene the world you built. Great game and great job! Good luck for any other projects you might have planned!