Thanks for playing! :)
Level 3:
The Shroom on the right was supposed to tell you to jump on the other guy and throw him with [F].
But i think it might be cut off a little and not very present on the screen.
Level 5:
The secret room is home to a shroom that pushes some levers to trap you - like most of them do. You don't have to find the room to clear the level :)