The Good
In fairness, the controls work alright in Dafox, and you'll jump across areas and perform basic combat moves against enemies pretty easily. There are some interesting power-ups too, including a fish that protects you from a fall, and a hour-glass that slows down time temporarily.
The Bad
Pretty much everything about Dafox is of a low standard, sadly. There's very little creativity in the animations or artwork, and the music really is dreary. While the controls work OK for the most part, there are times when they become unresponsive. Combine that problem with shonky collision detection, and you have a real mess on your hands. There are power-ups to unlock, but they're all pretty useless and upgrades require real money. For a bounty hunter, you'd expect a little more personality than a small smile at the end of each stage too.
The Verdict
Considering the far better platformers that are available on the market, you really shouldn't waste your time with Dafox. It's rather dull, often broken, and it lacks any sort of replay value. Go play - and pay for - Bit.Trip Run instead.