As some of the other comments said, the idea is great but we're lacking in user input after getting all the upgrades, and I think you could get away with making a small encyclopedia for echoes but a tool tip foor them would certainly be much more appreciated
Echoes are included in the encyclopedia. https://imgur.com/a/XpLccdT
Also as I stated in the reply for the other comment I am currently working on adding more content to the game. Working on this alone on my own free time :)