Congrats on your first game! It only gets easier from here :)
For a first game this was pretty good! I liked how the elements interacted with eachother. Also- it's cool that you decided to use some more advanced features of unity (particle effects!). Changing character behavior was also a nice touch.
I've encountered some bugs. The ant needs to gain speed to enter the pipe, and the cake can fall sideways, (apparently the I can't interact with the ant in that case). Also- the "interact" text could be bigger (ant it didn't appear on the ant and the rope in the end).
Over all- this was good (and for the fist game- really good). You clearly had a vision of what you wanted to do, and I think you might have achieved it :)
Keep up the good work!