Thank you for your comment.
Portal is one of my favorite games, so thank for reminding me of its wonderful game design.
Unfortunately, my manager told me to cut the corners, because jam games should be vertical slice of gameplay. It was decided: 1. mechanics with minimum viable tutorial; 2. exploring; 3. theme; were more important than voice over or openning cutscene. Also, my sound designer and my artist could do a better work! This would cover up dullness of gameplay, right?
The funny part is I am my owm product manager/game designer/developer/artist/SFXer.
And the only other people in our team are playtesters. They are not game designers, so they solved most if not all of my puzzles instead of dissecting them.
So thanks again for your professional opinion (it is not an often occurence - getting feedback from a real game studio founder)!