need to know What is it? A physics-based bridge construction puzzle game where you guide vehicles through a series of test chambers using (and defending against) Portal game technology.

Developer: Clockstone

Publisher: Headup Games

Reviewed on: Intel Core i5-6600K @ 3.50 GHz, 8 GB RAM, Nvidia GeForce GTX 980

Link: Steam Link

The little vehicle drops from a chute and speeds across a rickety bridge I've constructed. As the bridge collapses behind it, the vehicle drives through a portal that transports it to the other side of the test chamber where it rides off a ramp and plunges back through the first portal again. Its speed has increased so much from the fall that this time it launches from the portal with enough momentum to fly across the chamber to the exit, though it tumbles as it lands and sends two helpless passengers flailing into a pit of acid.

Yes, I've killed two people and pretty much everything I've built has crumbled. This was a triumph, though: the cargo made it to the exit, and in the Bridge Constructor Portal, that's all that really matters.

Much as we'd love a new Portal game, Bridge Constructor Portal definitely isn't one. It is, however, a good puzzle game about building bridges to usher vehicles safely through deadly test chambers, and it makes fine use of the memorable systems from the Portal games. Over its 60 progressively more challenging levels, you build bridges by connecting supports and cables to a test chamber's anchor points, and combined with portals (sometimes lots of them), figure out how to get vehicles from the entrance to the exit.

There are even weighted companion cubes that can be used to plop onto buttons

In some chambers, there are turrets that will open fire on your vehicles while chirping sweetly, the familiar propulsion and repulsion gels to thrust and fling your deliveries, rebouncing energy orbs that need to be guided (by banking them off bridge sections) into their sockets, and yes, there are even weighted companion cubes. These can be used to plop onto buttons or employed as shields and battering rams against turrets.

GLaDOS is there, too, acting as your mentor and voiced by the same actor from the Portal games, but if you were expecting the same level of humor from Valve's Portal games, don't get your hopes too high. The writing is sort of cute and while it's reminiscent of GLaDOS's cruel humor, it never really accomplishes it. That's okay, though. You're here for some fun and challenging bridge-building puzzles with Portal tech, and that it does accomplish.

Once you've solved a chamber, you can up the challenge by allowing a fleet of vehicles to run through the same course instead of just one. This isn't always hard: sometimes the bridges you've built for one truck can handle several just fine, but other times the added weight of additional vehicles will require you to build more, or build better, or rebuild completely, and the routes can be immensely difficult when portals have your vehicles crisscrossing or interfering with each other. The fleet challenges are entirely optional: beating a chamber with one vehicle instantly unlocks the next.

The progression from one challenge to the next is pretty steep: rarely did I feel the previous chamber had completely prepared me for the next, but experimentation is fun and a handy undo button lets you quickly remove and rebuild any embarrassing mistakes. You can test your solution at any time, even if you're not done—there's no harm done in letting vehicles explode, crash, and burn until you've figured out what the puzzle wants from you—and quickly get back to construction. As is important in trial-and-error puzzle games, success is satisfying, but failure is entertaining, too.

People can be replaced. Cargo is much more important.

There can be tiresome moments in Bridge Constructor Portal, which usually come when you've solved the puzzle mentally but need to fine-tune the physical solution. Helping a truck make a jump so it flies neatly through a portal without nudging the side, or so it lands neatly in some specific spot after a bounce, may require repeatedly adjusting one tiny joint of bridge or ramp over and over again until it's just so. If you're a perfectionist, maybe that's a selling point, but watching the same vehicle run the same course (there's no fast-forward button, unfortunately) multiple times while you make minute tweaks to one tiny portion of your design can try your patience.

At the same time, Bridge Constructor Portal is plenty forgiving in other respects. Remember the two little men who died a horrible death by falling into acid, but I still got a passing grade from GLaDOS? People can be replaced. Cargo is much more important.