Hate to bring this up here, but I don't have a PMC account. ever since the latest world update that updates the leaderboards, it hasn't been possible to start a new game while one is already running. I believe the same has been happening on the Realms version before the update too.

After some investigation, it seems to be a fixable issue. The issue is within the function kk:items/give, specifically within:

item replace entity @p hotbar.7 with written_book{title:"[Punch] -> Reveal || [Use] -> Game Controls",author:TheAl_T,pages:["{\"color\":\"dark_blue\",\"text\":\"     Game Controls\\n\\n\\n\",\"extra\":[{\"color\":\"dark_green\",\"text\":\"           Easy\\n\\n\",\"clickEvent\":{\"action\":\"run_command\",\"value\":\"/trigger trigger set 1\"}},{\"color\":\"gold\",\"text\":\"          Normal\\n\\n\",\"clickEvent\":{\"action\":\"run_command\",\"value\":\"/trigger trigger set 2\"}},{\"color\":\"dark_red\",\"text\":\"           Hard\\n\\n\",\"clickEvent\":{\"action\":\"run_command\",\"value\":\"/trigger trigger set 3\"}},{\"color\":\"black\",\"text\":\"         Tutorial\\n\\n\",\"clickEvent\":{\"action\":\"run_command\",\"value\":\"/trigger trigger set 4\"}},{\"color\":\"white\",\"text\":\"      Secret Level\",\"clickEvent\":{\"action\":\"run_command\",\"value\":\"/trigger trigger set 5\"}}]}"],HideFlags:24,CanDestroy:["minecraft:white_wool"]}

The title of the book is too long, causing the entire thing to be invalidated. Resolution given to [MC-59153] by Searge says it's intended, so the name just has to be shortened somehow. The exact length allowed seems to be 32 characters, so some compromises have to be made.

Ey, it's all in good fun. Take your time!

Yoo you're still around?