RetroPie comes without the Raspbian desktop client, but it can be installed (either from menu, or manually with:
sudo apt-get install –no-install-recommends lxde
sudo apt-get install xorg raspberrypi-ui-mods rpi-chromium-mods
startx # to start the desktop client, but do next two steps first to install chromium
wget https://github.com/kusti8/chromium-build/releases/download/netflix-1.0.0/chromium-browser_56.0.2924.84-0ubuntu0.14.04.1.1011.deb # custom compiled Chromium browser which includes Widevine DRM (needed to watch Netflix)
sudo dpkg -i chromium-browser_56.0.2924.84-0ubuntu0.14.04.1.1011.deb # install the downloaded package
Thoughts / experience
Both the desktop client and Netflix opens nicely, but there are some issues when streaming. First; sounds is low (lower than on games in RetroPie), and picture quality is not very good. Also, after watching for about an episode, the picture starts to flicker and lag – I guess it’s because of overheating. Will try to look into this and see if things can be improved.