Shing! is an innovative beat em' up where blade attacks use either the right stick or mouse movements to perform different attacks depending on your input device. It's a bit hard to get used to, but the system grew on me eventually and it's hard to complain when a developer tries something new.
However, because of this I think it's hard to recommend Shing! to the general public, newcomers to the genre probably want something more standard to start out. Also, new mechanics must be hard to implement so it's not gonna be as refined as a standard 3 button setup right away either.
Besides that I think the presentation is good, the designers use lighting and color to great effect and there's decent enemy variety which helps make each encounter feel distinct. Not to mention an abundance of different power-ups.
Another notable aspect are the writing and voice acting, the humor even gets a bit lowbrow at times, but I think it's good for the most part, I have to admit. It's never pretentious or annoying and the actors do a great job. I also like the character designs and there are plenty of unlockable costumes.
To conclude, I think Shing! is pretty good. I'm unsure of how to judge a game that's so different from the norm, but I think it's very fun and I'm glad I played it.