The first thing you need to know about Tag: The Power of Paint is that it's the indie version of Portal. It has the same strength of design and the same unity of vision as Valve's trailblazing effort, and it evokes the same amount of gee-whiz incredulity as the first time you stepped into Chell's heel springs and shot a portal.

But do you know what's even more incredible about Tag? Industry professionals didn't create it; a group of game-design students known as The Tag Team did -- no relation to the early '90s one-hit wonder. The team took home top honors for a student entry at the 2009 Independent Games Festival. All it costs is 50 megabytes of your hard drive space. If you love indie games, do yourself a favor and hit the jump.

Tag (downloadable here) is a game in the first person that is all about interacting with a physical space. Much like Portal, or even Mirror's Edge, its focus is on critical, spatial thinking rather than killing zombified space-Nazis -- shooter junkies need not apply.

The fundamentals of the game are simple. The world is grey, with very little interface by modern FPS standards. You can't jump on your own, and you can't shoot bullets. But what you can do is enliven Tag's humdrum landscape with a bit of color.

In Tag, you interact with ablilty-granting splotches of different paints that litter the world. Eventually, through the game's paint gun, you gain the ability to paint these splotches wherever you like. Green paint makes you jump, red paint makes you speed up, and blue paint makes you cling to the surface that it's painted on.

Like I said, you have no jump button, but you need to travese large gaps. It doesn't take an experienced gamer to realize what the combos of these three functions -- or paints -- ramify.

You can spray a trail of red paint with a bit of green at the end. As you speed down the line of red and lift off of the green jump, toward a vertical wall, you can quickly switch your gun to the blue climbing paint. If you speed up, hit your jump correctly, and spray the climbing paint, you will land safely on the wall you aimed for...and the orientation of the level will shift.

Your original horizontal plane, now switched vertical, is above or below you. This is first-person acrobatics at its best. Puzzling your way through the game's environments is exhilarating.

At first glance, Tag's low production values and poor soundtrack may seem off-putting. But that's part of the charm. The whole thing smacks of studious thought and design, and the game only glitched on me once. Just be sure to bear in mind one thing: A few DigiPen students created it. Their assignment was to manufacture a game engine.

As it turns out, they designed a damned good game, too. I hope they got the A.