Space Nubra Volume 1
Publisher: Ero Ero Ohkoku
Aiming and zooming using your scope, you must use the 2ch cat character's gigantic metal penis gun whose lasers disintegrate clothes to strip the sleeping schoolgirl before she catches you and closes the window. At random, she will turn over, and on successful hits she will open her eyes; if you shoot her while her eyes are open, she will close the window and the game is over. Successfully stripping her naked nets you a few pictures.
You can play this game at this link.