NICE! Great job in dishing it to the big man~
Those walls are destroyable using Crash Man's weapon! It'll help you to avoid enemies, pass through the stage quicker, and most importantly - paired with your Items, it will help to grant you access to parts of the map which have the 1-UP, and the E-Tank -- which refills your health! You'll also be in the path of Weapon Energy and Life Energy, to help you to complete the stage
And, cheers~ I suppose there's not much to spoil gameplay-wise for Portal
but if I have questions, we'll come running!