After reading about it, I was disappointed that the game Flower wasn't available on PC. But fortunately, someone on the discussion boards drew our attention to Cloud, which is similar and is freely available. Actually, the game's Wikipedia entry links to ThatGameCompany, the company that created Flower.
What is Cloud exactly?
This videogame transports the player in another dimension: it's as if he/she is acting in his/her own dreams: the artwork of the introduction to the various levels, the colours, the music, clouds - the object themselves, everything reminds someone of their best dreams. As such, this kind of videogame is likely to stimulate the players' imagination.
With that in mind, the word experience, which Fiona used to describe this particular kind of videogame, seems quite appropriate.

Guiding the clouds to shower the land
A particular kind of game
A closer look at its feature and design reveals that it is nevertheless a game or ludus, to reuse Frasca's proposed modified meaning of Caillois' word (in Newman 2004). In effect, Cloud:
has goals such as gathering the clouds, drawing a lollipop, preventing dark clouds (smoke?) from reaching virgin lands, showering the lands
is made of several levels of increasing difficulty
contains other scaffolding features such as:
- a training module as an illustration of the Subset Principle (Gee 2003, pp. 121-122) which teaches players the basic skills they will need later in the game
- feedback tips
requires the player to adapt his strategy. Even though I haven't played enough to succeed in the third level yet, one approach that worked better was to divide the bright clouds in several parts and with each of them, pushing light grey clouds towards the dark clouds. This is a good example of the Ongoing Learning principle (Gee 2003, pp. 69-70)
We may further categorise Cloud by saying it is a form of mimicry game (Caillois 2001): the player is an illusory character that one might call the “Guard of the clouds”. As we said above, what gives it this experience-like nature is its design in terms of graphics, music, interactions. But thinking about it, the word experience may be yet another way to talk about mimicry and role-play: the player experiences being in someone else's shoes, using special powers, etc.
References:
Caillois, R. (2001). The classification of games. In Man, play and games. Urbana, Ill., University of Illinois Press; Wantage: University Presses Marketing.
Cloud (2005). Role-playing videogame. USC EA Game Innovation Lab.
http://intihuatani.usc.edu/cloud/
Gee, J. P. (2003). What video games have to teach us about learning and literacy. New York, Palgrave Macmillan
Newman, J. (2004). What is a video game? Rules, puzzles and simulations. Videogames. London, Routledge.
Keywords: e-learning, IDGBL2009, nature, video_game