Experiment makes point-n-click adventuring a fresh, fun and unique experience. It can drag a bit, though.
The story evolves very slowly. Very, very slowly. There is some good character interaction later in the story (no spoilers here), but it takes a good long while to get there.
The game is not without some technical quirks that make it a bit more frustrating than it needs to be. Sometimes you'll need to wink the same light on and off three or four times to get Lea to find all the details. It leads to many segments of repetitive gameplay -- you flick lights unnecessarily just to be sure you've found everything.
Tracking what you're supposed to be doing takes effort as well... you do have a log of "to do" items, but thr murky and uneven camera views, while realistic, make it quite challenging to figure out what's important and what isn't. You'll spend a lot of time having Lea wander about with little idea of how to proceed.
Something else missing from the game is any real sense of danger to follow on to the creepy environments. While I'm not a fan of danger for danger's sake, I felt like there needed to be some tangible dangerous elements in the game. As it stands, you can't get stuck or killed (except for one segment near the end), so tension at the slow, creepy world around you gives way to... well... boredom. You'll solve similar puzzles several times, read through many similar letters, etc. The story is what will keep you going, not so much the gameplay.
As a whole, the visuals and audio are well done. There are a lot of nice, atmospheric sounds, bits of good ambient music, and Lea's dialog is all verbally spoken and well acted. The video is realistic and well done, but again I think is a bit too murky and realistic, causing some frustration in hunting for things of interest.
Overall, Experiment is a very good game, and a wonderful concept. I just found it to bog down in some repetitive game elements and to be about 5 hours or so too long.