WMG / The Floor is Jelly

This game is a Metroidvania.
Considering there are areas that contain multiple windows that take you to more areas each, and the fact you can backtrack through them, and the fact that Word of God has hinted at hidden areas that can only be revealed by looking at every nook and cranny, it's not hard to consider this a possibility.
  • Comfirmed, sorta. The game's areas are all connected to a central underground area, and you can revisit them as much as you want.

Humans once resided in this world.
Considering the fact that furnished houses are present in this world, there's a possibility that humans once resided there, although living inside them would have been tricky as the houses would bounce back and forth due the ground they're resting on wobbling from the movement of any nearby things, not to mention the movement of its residents inside as well.

The game is All Just a Dream.
Considering that the world entirely acts like jelly, it would be hard not to have fun bouncing around all over the place. Sadly, such a fun world would eventually be revealed to be a dream, and by the end, your character would wake up in bed in the real world and be disappointed to discover that everything's stable, which brings me to...
  • Debunked.

The final area is all solid and still.
This would take place in the real world after you're character's woken up. After leaving the house, you go through areas that looks like all the other areas in the game, except the ground is all solid and no longer bouncy or wobbly. After running around a while, the credits roll.
  • The very last area of the final stage being solid is confirmed, but in a different way. It does, however, return to normal bounciness just before the ending credits.

The 100% Completion reward will let you change the individual properties of the jelly as seen in the final stage.
This would seem the most logical thing, as the computers in the houses have a mysterious command called "SET" that isn't available until all 31 of the houses are found.
  • Confirmed! The command lets you change three values that define the jelly's behaviour: DECAY, POWER and TRANSFER.

The Updated Re-release coming to Steam may include a "jelly quake" secret mode.
Word of God has already confirmed a new secret game mode coming in the Steam update, but there may be more secret modes coming. I propose that there would be another secret mode in which every platform starts being jiggly each time you enter a room... and stays jiggly. Such a thing is already possible if you play around with the values as described from above, but in that case the platforms would only be jiggly if the player disturbs them.
  • Jossed.

The update will add one more house.
There are 31 houses, which is an odd number to end on. There should be one more added in to even it out, and should be hidden somewhere in the Hub Level, the only location that has no houses hidden.
  • Jossed.

One of the achievements will require you to Speedrun the game.
With the game coming to Steam, adding achievements is a possibility. Considering the type of game this is, one of them will probably the obligatory speedrun achievement requiring you to beat the game within a certain amount of time, likely in less than an hour or even 45 minutes.
  • Confirmed. The speedrun achievement requires you to beat the game is a rather tight and limited 30 minutes.