Great dialogue and character portraits! I was enraptured all the way up until it abruptly ended. I'm excited for a full version!

In the full version, I'd really appreciate these things:

• Run button / faster movement speed
  Current movement speed is akin to an arthritic sloth. The game as a whole would be improved if less time were spent waiting for your character to get to the other side of a room.
• More unique transformations / transformation sequences
  Recolors of the protagonist aren't very interesting, and it's difficult to see the perspective of a silent one. For a TF game, it needs more TF.
  Give us some descriptions! Midori can't hog all the slime fun here.
  Ideally, any seen dialogue bits (including seen TF sequences) should be skippable so as to not make the player sit through them repeatedly.
  (Midori's whole situation is perfect, though! I love the social situation Midori's in, it's very unique to this game. Very strong character.)
• Slightly less tutorials / Midori not figuring out what things do for you
  When you put the player in a room with one new slime, a fire, and nothing else, you don't need to tell the player to use the slime on the fire.  They have no choice other than to do so. The current encounters are fine, but I think it would be nice if Midori was surprised by the player's inventiveness when they solve a puzzle like this.
• More dialogue branches / let the player influence dialogue slightly
  I don't expect much for this, but little interactions like wobbling a slime over to the window for Midori to see and Midori going all "wow it's so neat to see you do that in person" would add a lot of charm value to the game. Any small thing that the player can optionally do that can be acknowledged will be appreciated by the players who take the time to do it, especially if their efforts are acknowledged in later dialogue as well. See: Undertale's phone and calling Toriel.

I really hope you continue this story. This is already quite a fun little game, and it would be a shame if this story didn't get a proper finish.