Have you played the game Bridge Constructor? That game was awesome.
This looks like pretty much the same thing, but I do like the aesthetic you've gone with and I like that you are including different more interesting win conditions (two cars coming head on / two cars entering the stage at different levels).
The most fun I had with Bridge Constructor was not in finishing the really challenging levels, but with experimenting on the earlier easy levels in creative ways (for example I tried to beat the whole game only using bridges that contained jumps).
Also there was a real cheese strategy to beat that game where you could make a reverse suspension bridge (by running a cable below one long piece of bridge and creating a swaying rope bridge kind of thing). I thought they should have included some kind of structural damage that builds up over time with bending to avoid cheesery. Just my thoughts about bridges, bridge construction, and bridge enthusiasm.
Hey, yea I've played Bridge Constructor and most of the other bridge building games over the years.
It has definitely become a more established genre in recent years.
What sets Poly Bridge apart is a bit more complexity with the building blocks (mostly around hydraulic pistons that allow shape-changing structures and draw-bridges) and the Sandbox mode which will allow you to mess around with layouts of levels, materials, vehicles, ships and all the game has to offer.
You'll also be able to submit your Sandbox levels as puzzle levels for other players to try and solve, and you can very easily share animated GIF replays and upload them for everyone to see.
Hopefully these community oriented features will encourage sharing and create an ecosystem with countless more levels to play and enjoy.
Thanks for the feedback and information around the bottom suspension bridge "cheat", we'll keep an eye out for that and I have been trying to fine tune the physics values so to avoid any tricks in solving the puzzles.