Yes, a flail game ! I've seen a lot of games that tried to add some strange mechanics to that (with platformers, obstacle-only, stuff like that), but finally, I've found just a brutal flail to swing in the enemies face !
The concept is simple, but effective, and I liked having a lot of space to swing, while needing to maneuver carefully -but quickly- when the enemies were closer. Also, compared to other similar games, I really liked that the play was invincible and needed to protect something else, it made swinging the flail without worrying really fun !