It's fun, but perhaps a bit too easy on Hardcore. Some suggestions for making it a bit more challenging: Give less time to unzip the skirts on harder difficulties, and start the player with fewer lives.
As far as making comboing easier, the TVs are nice, but pale in comparison to being intentionally seen and then shutting a door and stealthing. The girls arrive so much faster with the latter method. So, something to rebalance the difference between the two would be nice.