Amazing game I had soo much fun. ^-^
In case it will help someone I'll post here what i did before ED 14 activated for me.
When I got the ED 1 I had total of 11 endings. Then i returned for the rest (this time i skipped most of the puzzles since I wrote everything down) and got ED 4 And 13 and closed the game. Then I realized that there is in fact 15 endings and got ED 9 and ED 14 just triggered.