The Windows95 boot theme is based on the template provided by http://brej.org/blog/?p=174
It is meant to simulate the Windows 95 boot screen and shutdown screen.
The RetroTux boot theme is based on the xubuntu-logo Plymouth theme.
Copy the theme folder into the Plymouth theme directory.
sudo cp -r Chicago95/Plymouth/Chicago95 /usr/share/plymouth/themes/
sudo cp -r Chicago95/Plymouth/RetroTux /usr/share/plymouth/themes/
Add to default.plymouth
sudo update-alternatives --install /usr/share/plymouth/themes/default.plymouth default.plymouth /usr/share/plymouth/themes/Chicago95/Chicago95.plymouth 100
sudo update-alternatives --install /usr/share/plymouth/themes/default.plymouth default.plymouth /usr/share/plymouth/themes/RetroTux/RetroTux.plymouth 100
Choose the theme to load. (As you run the following command there will be a number assigned to each theme and located in the first column of a list. Use that number to specify the theme and press enter to continue.)
sudo update-alternatives --config default.plymouth
Update initramfs
sudo update-initramfs -u
Install Plymouth to your system (ArchWiki)
Copy the theme folder into the Plymouth theme directory.
sudo cp -r Chicago95/Plymouth/Chicago95 /usr/share/plymouth/themes/
sudo cp -r Chicago95/Plymouth/RetroTux /usr/share/plymouth/themes/
Set the theme as default to use
sudo plymouth-set-default-theme -R Chicago95
sudo plymouth-set-default-theme -R RetroTux