I would suggest you going with premade levels, or a random combiantion of premade parts. Firstly, nobody will notice, people play gamejam games about 5-15 mins, so it is hard to see procedural generation. Secondly, it is way easier and since you ask this question it would definately be a challenge in itself.
But anyway, to generate something like this, you can use any of the maze generation algorithms. They are pretty straightforward. After that choose a random number of how many walls you want to leave in level and simply delete a random wall until you have that many walls.
168 days ago(+1)
I agree with Alex, I think the walls are designed using a maze generation algorithm then randomly clearing some walls from the maze to make it more open.