Alot. We originally were going to have 8 levels (and an extra secret one) along with a seperate tutorial.
Our puzzled were supposed to work forward and backwards.
We wanted an undo button
An item box showing what item you currently had
And arrow controls (we basically made our own movement system because we didnt think that the tile movement would cover what we were doing. We also made our own controller using the touch controls because it also doesnt seem to currently have a way to swipe.
All of the above we didnt do due to time constraints and not thinking we would finish in time.
We also wanted a much better menu, end screen, first level, final level (the level where you find your dog was going to have an actual puzzle), tutorial.
We also had a bunch of art we didnt add in such as
Boat animations while in water
Unenterable forests instead of walls
A better boulder
A background
Buttons
The above art we had but didnt add in due to time constraints (by the time I even got the file back from the artist there was 4 minutes remaining!!!
We also had ways to change the volume of the music and sound effects (separately) as well as the swipe distance.
That wasnt done due to not understanding enough about how to do something like that and we only had 3 hours left at the point I was adding menus and the pause menu.
A bigger restart and menu button would have been good but by this point it was really late for our artist so they couldn't design it.
We also had 10 people test our game about 30 minutes before. However we didnt have time to ask them about how they solved levels so level 3 is "cheese"able (and it seems most people solve it this way.)
Overall one more day to polish and get the last few things in would of been perfect. This is why schedules are important.
The one thing that I regret not adding at the start is a schedual. That is my biggest regret.