Itchio messages are my preferred method of communication, it's nice when the questions (and answers!) are located next to the game for assets in particular and I check my messages at least once every day (unless something really serious gets in the way).
1) The flashing white rectangle that's overlayed on top of the highlighted menu option? It's in the script ggui_draw. It's actually drawing a rectangle with vector drawing instead of drawing an asset.
2) No. I'm kinda scared of implementing stuff like this because I always worry they'll go wrong and delete someone's progress, so I prefer leaving the responsibility to the player's operating system.