You can currently grab Poly Bridge 1 & 2 at 83% off, a fairly decent deal - you can also grab them individually also with some form of discount applied
Unleash your engineering creativity with an engaging and fresh bridge-building simulator with all the bells and whistles. Enjoy hours of physics-based puzzle solving in the Campaign and then jump in the Sandbox to create your own bridge designs and puzzles!
link: https://store.steampowered.com/bundle/27849/Poly_Bridge_12/