sanderdog is a chrooted underdog linux. It doesn't mount directly under the rootfs layer but instead creates another aufs rootfs and run its applications in chroot it has desktop integration except file associations (this might need workaround). It doesn't ruin the existing linux installation because it was mounted as read-only.
How to use:
1. Install sanderdog pet package and reboot the computer
2. enable rc.sanderdog in puppy service manager or make /etc/init.d/rc.sanderdog executable
3. Goto sanderdog gui to select linux partition
4. Click start
NOTE: Sanderdog works only if save was loaded or using PUPMODE 2