Unfortunately this hlunp.exe creates a (very) few corrupted files. You can check this for yourself by glancing at the bottom of hl2\scenes\k_lab\teleport01a.vcd. I have found and recommend another tool: GCFExplorer v1.5 by SASiO. Although it is a GUI tool and not scriptable from the command-line, it did the job for me.
List of corrupted files from hlunp.exe
Models
Gman_gestures.ani
Roller_Spikes.dx80.vtx
reciever_cart.vvd
Materials
brickwall052d_normal.vtf
brickwall052e_normal.vtf
metalwall042a_normal.vtf
breen_fakemonitor_.vtf
gooinglass_normal.vtf
Scenes
teleport01a.vcd
Sounds
Drone2LP.wav
sewer_air1.wav
exp1.wav
exp2.wav
explode_1.wav
swamp_bird4.wav
portal_beam_shoot5.wav
machine6.wav
slicer3.wav
wall_loop1.wav
wall_move3.wav
wall_move4.wav
door_squeek1.wav
fly1.wav
dog_alarmed1.wav
dog_alarmed3.wav
dog_angry1.wav
dog_angry3.wav
dog_servo2.wav
fz_alert_close1.wav
residentialblock.wav
laser_burn.wav
pz_alert1.wav
pz_alert2.wav
pz_die2.wav
pz_pain1.wav
pz_pain2.wav
br_synapse.wav
mo_talkingabout.wav
question23.wav
monk_helpme02.wav