A Rube Goldberg Machine

🎵 don't break my heart 🎵

this is a simple Rube Goldberg Machine, the main player (big red ball) comes down and hit a series of structures, breaking the heart of no gravity little red balls. 

remain problems: 

1. how to make a hinge joint using spring/damper/limit?

2. how to set up depth of field so that some ballon flies towards the screen would get blurred?