is your blog marked nsfw? Bc if not it really needs to be just bc of the BTD game. it's not okay if minors can find that and right now it's pretty easily searchable. your warning in your description doesn't mean anything unfortunately cos your blog is still just open and while i like BTD it's not good to just have it out in the open on a blog not marked nsfw
Did you know that Tumblr has a default safe mode (it seems to work pretty ok) which basically does the above and that you need to manually turn it off in order to see certain tags?
If someone actively ignores or bypasses the warnings and safeguards put in place either by me (the descript warning, appropriate tags, most nsfw hidden by readmores etc) or Tumblr itself, then that’s their decision and perhaps they should be culpable for it.