They are all on the same form, which is more like an interactive art / emotional experience / poetry-in-motion rather than a game. If you like this kind of game, I highly recommend you to try Flower and Journey, both are from ThatGameCompany (I'm not affiliated with them whatsoever, just a huge fan).
Now I've never tried this Bientôt l'été, but judging from the trailers, screenshots, and the discussions here, I think if you enjoyed or at least find Bientôt l'été interesting, then the two games would blow your mind away. Especially Journey, a game
an experience chock-full of metaphors all beautifully seamed together, and the multiplayer system works much better:
- At each map you may or may not meet at most one other random player (and when you get separated you may never meet him/her again),
- There's no way of identification (not even gender!) other than a randomly generated symbol,
- The only way of communication is to make a ding sound.
Strangely, this lack of identification and communication, and the fact that each encounter is volatile, makes you feel a sense of bond with the companion.
Another brilliance from Journey, is how each map (in my personal interpretation) symbolizes the different stages of man's life, from birth, toddler, childhood & school, youth, adulthood & work, maturity & wisdom, old age & eventually death, the after-life, then life goes full circle (the meaning of the ending =) )