Engineering is structural magic and bridges are amazing feats of engineering. Therefore bridges are elite wizard-caliber magic, which is why building them makes for such good puzzle gaming. You start with a few pieces and a budget, fit everything together as best you can, and hope the final structure can pass its test, or at least not collapse into the drink until after the final vehicle has crossed over. Bridge builder games are fairly common, but Poly Bridge sets itself apart with a cute low-poly style and playful set of puzzles.
Like any construction game worth its girders, Poly Bridge starts off with a few simple ideas. Lay down the road, reinforce it with cheap wooden beams, call out the heavy-duty iron girders when real muscle is needed, etc. Initially everything is locked to a grid, but after a few puzzles you can choose to turn that off if you want to go with full analog placement. Personally I found the grid small enough to allow plenty of free-form creativity while also letting parts line up with perfect symmetry, which may not be all that important for completing the level but certainly goes a long way towards making the resultant creation look pretty. Each type of material can only stretch so far, and having a grid to line things up against means you can eyeball precise measurements more easily. You don’t have to stretch a component to its full length, of course, but when lining up 3/4-length beams equally on either side of an arch it’s always good to have a precision tool on your side.
Symmetry only lasts so long, though, once Poly Bridge starts pulling out the more clever challenges. When you don’t have enough road to cross the river then it’s time to jump, but the problem with jumps is not only sticking the landing, which will frequently take several times to get right, but compensating for the weight of a car crashing onto the down. A precision curve tuned to the landing of the car helps, but there’s still a lot of downward force to account for even with a smaller car. Figuring out how to not only support that weight but do it cheap takes experimentation and an eye for stress management, as you figure out if a heavy steel beam may be needed or if you can just run cable to the necessary section.
Then Poly Bridge introduces the pneumatic piston, which initially seems to be there just to make drawbridges for passing boats but quickly becomes a primary factor in making more elaborate creations. Want to raise or lower an entire section of bridge? Pistons are your expensive best friends, although you’ll need to pay attention to structural integrity as sections that rely on each other disattach and reattach, changing the load on different sections of the bridge as it moves. If the only weight the bridge has to carry is a small scooter you can get away with a few attachments, but a VW van is going to take a little more structural voodoo to support.
It’s the underlying physics engine that makes Poly Bridge work so well, modeling every bit of stress on each beam of the structure. That’s how all bridge-builders work, of course, but there’s still something lovely about hitting the space bar and watching your 2D blueprint change to a fully 3D isometric view and being able to track each individual turning from green to red as it bears more of the load. Physics also helps as the bridge shatters under the weight, collapsing in a unique way as everything falls into the drink. When the fragments of your best plan yet end up a broken mass of struts and beams at the bottom of the river, it’s good to know that you put your own personal design stamp on the wreckage.
Once you’ve completed a few challenges and gotten a sense of what the pieces can do, it’s time to hit the sandbox. Set the river width, types of vehicles, and then go nuts seeing how the various pieces can be fit together to make engineering monstrosities. You can upload your best creations to the Steam Workshop or download the hundreds of puzzles the community has made available. Poly Bridge has an active community and the developer web site even hosts a number of .gifs of some of the more entertaining creations or crashes.
There’s a lot of engineering magic required for Poly Bridge, as you wrestle solutions from a handful of girders, some steel cable and a bit road. Sometimes you can build something elegant and beautiful, and others a frankenstinian beast of a bridge that’s can be viewed as semi-functional at best. If it works, however, that’s called Victory, and the feeling you get when debugging a particularly argumentative structure is what puzzle gaming is all about.