Getting the double jump here means more backtracking!... fun. There a few things I forgot to get that I could get now but I get them in later videos, It's all Memories so it's not that big of a deal.
18:10 is where the actual entrance to Lonely Wasteland is, it confused me a lot when I first played this game so hopefully you didn't get confused as well.
4:25 - Third Letter Memory
5:14 - Dash Invincibility Addition Module
6:52 - 02.wav Memory
8:51 - Promotional Material Draft_Final_Edit Memory
11:15 - 03.wav Memory
20:45 - Torn First Page Memory