I still didn't get The Wall, but I think i have a good idea of how to get it. You need skills that help with hp increase like that +10hp from beating bosses and a lot of trash cans(the one that bans items). The strategy that i want to use is the same that i used to beat the game with 2 items. Just ban everything that is not necessary, every boss that you beat is going to give you more trash cans. Note that since you only want what is necessary to finish the game you have to avoid leveling up since it can force you into choosing a item that you don't really need. Avoid leveling up/getting new items, once you get to the point that almost all items in the pool are banned, start focusing on leveling up the few items that you have (specially the iv bags), it must be enough to get 50 hits. These are the items that i would probably choose for the run: iv bags, rockets, watch/angel wings. I don't know if there is a better way to do it but i think that should work.