Portal Pro is a set of test chambers focusing on solving puzzles locally rather than using complex fling techniques. The goal here is that the solutions are hard to come up with but easy to actually do.
While it isn't as good as Rexaura (Which is a known fact), Portal: Pro is an amazing mod that should be played by anyone who owns Portal on PC. The puzzles are perfect. They appear very simple and easy, but usually have a little trick that makes you think much harder. It is also rather long for a Portal mod, which is good. Thirty great puzzles along with five secret maps for players to enjoy. The only problem is the last chapter, the BTS maps, where it gets a little confusing as to what you are meant to do. That, along with the boss battle brought this otherwise amazing mod down a bit.