Are you into intense, fast, and satisfying sword-fighting action? Nidhogg is just that.
Nidhogg has simple, intuitive controls, but a lot of moves to master. You can play with bots, which get progressively harder every level, but Nidhogg reaches its peak when you have someone else to play, scream, and battle with. The online multiplayer certainly needs a lot of work, but local multiplayer is really fun and fast-paced. The ability to play in tournaments is also really good, if you're having a party with a lot of people. With various different moves and tactics Nidhogg gets super heated. If you don't like the way the controls work, you can just configure them yourself! The soundtracks meet the battle to a T and the stages are amazing.
However, this game does have some flaws. The online multiplayer is pretty bad, considering the fact that it's pretty laggy, and more often then not, the host has some kind of advantage. If you're only looking to play online and don't enjoy playing with bots or don't have friends over frequently to play locally, this game may not be right for you. This game also has only four (albeit beautiful) stages and overall doesn't have a ton of content for ~$15.00.
So, tl;dr, this game has awesome speedy sword-fighting down completely. Good music, good stages, and decent "replayability". Fun is increased when you have more friends to play with, but online play is not recommended and may be a bit small for $14.99 (plus tax).