The Experimental Gameplay Sessions talk at last year's GDC was one of my favorites, but also one of the most useless for me as a blogger -- designers showed up and talked about their experimental games, but most of the games were already available and those that weren't might one day be turned into full-fledged projects.

To be honest, this year was no different in that respect. I had a great time seeing all the experimental games, but you'll have a significantly less-great time reading about the ones you can't play. On the upside, though, more than half of the games are indeed available (usually for free), so if nothing else this very brief rundown of the session might work as a brief list of interesting indie games to check out.

Hit the jump for more.

The highlighted games were:

Flower

Achron

ROM CHECK FAIL (To the creator, the game shows the strength of constant gameplay variation where change itself becomes a challenge)

Where is My Heart (Contiguous gameplay space presented noncontiguously)

Closure (Where "dark levels" in Legend of Zelda or Gears of War make dark obviously bad and light obviously good, Closure attempts to muddy this)

Indie roguelikes presented by Derek Yu (Spelunky, The Sewer Goblet, Dwarf Fortress, Real Lives, and ChessRogue)

Miegakure

The Trials, I Wish I Were the Moon, Storyteller, and Fate

The Unfinished Swan

Shadow Physics

Spy Party

You can pretty much figure out for yourself why the ones that can be played or watched are experimental, but I'll try to summarize the unreleased or more unusually explained ones.

Jenova Chen and Nicholas Clark of thatgamecompany showed the audience many different prototype versions of Flower, starting with a goal-free wireframe version where the player simply moved the leaves around by creating gusts of wind with a mouse, to an equally goalless (but beautiful) grass field, to populating that field with an invisible player avatar who can eat and bloom flowers at will, to a seed riding wind currents looking for a place to plant itself, to a petal swarm not unlike what was eventually released. The petal swarm prototype elicited questions from Sony execs, who wanted to know where the depth and challenge would come from. thatgamecompany tried a bunch of different challenge-based versions of Flower including a rollercoaster-esque linear version, survival challenges, and even a version with spells and light RPG elements. Eventually, they decided on the current version because it prioritizes tgc's initial design ideals of peace and harmony. The idea of "hard fun" was counter to their goal, and so they scrapped all the challenging stuff in favor of what you can currently download on PSN.

Miegakure by Marc ten Bosch was a platformer wher ethe player can move in four different dimensions -- and the fourth dimension is not time. I find it almost impossible to explain in words because I honestly did not understand what I was seeing; the player avatar would move around a 3D plane and after a button press, the plane would contort and compress and turn into a totally different area which could be manuevered around and manipulated so it could have an effect on the initial 3D plane. It just looked to me like hotspots were hidden in certain areas of the environment that acted as portals to different areas, but it's undoubtedly way more deep and complex than that.

Shadow Physics by Flashbang Studios is a platformer which takes place in a 3D space, but you control a character who can only move on the 2D shadows cast by 3D objects. By moving light sources and the actual objects in the room, you could create different platforming opportunities for the shadow avatar.

Achron is an RTS where time travel is a resource. At any time, assuming you have the chrono energy, you can move to any point, past or future, in a fight. By way of example, the two creators were playing against each other and the red team successfully intercepted the blue team's mining base. The blue team leader then sent back a cadre of soldiers to help defend the base, which they did succesfully. Bitter, the red team leader went into the future, researched nuclear technology, then went back and time and blew up the entire mining center with a nuke, killing blue and red soldiers alike. The blue leader then went all the way to the beginning of the battle and prevented himself from ever building the mining center in the first place. Since the red team leader's actions still existed in this universe without a mining base, the red team leader eventually ended up nuking an almost-empty plot of land with nothing standing in it except for his own soldiers.

The Unfinished Swan by Ian Dallas was meant to be interesting in the same way a children's book was; visually-oriented, simple to pick up and play, relatively short, and not full of arbitrary puzzles or challenges. Dallas admitted that he caved after a while and added puzzles anyway. The game is not done yet but Dallas has opened a company to develop it, and he's looking for programmers and artists.

Spy Party by Chris Hecker is a two-player game inspired by an inversion of the Turing test. The Turing test is so difficult for a computer to succeed at because language is so complex and difficult that only humans or truly functional AI could master it in a realistic and believable way. But what if you made the language very easy and instead of a computer trying to be human, you made a player try to act like a computer? Two players -- one a spy, one a sniper -- are in asymmetrical competition. The player must move around a party completing objectives that the other AI party guests will not even attempt to accomplish. Everytime the player accomplishes one of these objectives, they give a slight "tell" -- if you try to bug an ambassador, the player's hand will dart out and suddenly retract, just like if you try to steal a book, you'll motion to put it back until suddenly shifting it into your coat. The sniper's job is to look at the crowd and figure out which of the dozens of characters is the human spy, and kill him. As it stood the game was almost exclusively based around recognizing these little telltale signs, but Hecker planned on expanding and deepening the gameplay.