Exterminate rats with a giant sword! What could be more fun!
Normal controls, A (space/z) to swing the sword, blah blah you get the gist. There are extra options in the menu for deleting your saved data and for unlocking the last level if you really want to skip the first 6.
Yes, I did purposely rat-spam the last level, making it ridiculously difficult, because it’s really funny to see a massive swarm of them coming at you and it looks really cursed, especially if you group them all up and have a line of them. I personally have yet to successfully beat the last level because I’m evil and added all those tight areas filled with rats 
Have fun and don’t let the basement rats bite!