TWIP has posted a pitch deck for Angry Birds pinball that was never made. https://www.thisweekinpinball.com/the-twipys/
Looks pretty fun, to be honest. Pops instead of slings are a huge breath of fresh air these days, the rotating, sinking castles with targets or locks are a cool idea and the return of the Black Rose rising cannon mech makes sense for the theme, which would have appealed to a younger demo than most pin themes these days. Shame it didn't happen.