Each head has its strengths and weakness and can be used for different tasks. The jar head that you start out with, for example, can be upgraded so that Fred heals faster when he's wearing it, but he'll drown in deep water. With the stone head, he's safe underwater and can smash open cracked walls.
By the same token, each head is particularly strong for fighting a particular enemy and weak against other enemies. You can also purchase head upgrades, but they're expensive.
Aside from the head-swapping (and I never got tired of the animation for that, simple as it was, or the fact that each head made Fred move in a completely different way), the gameplay is fairly familiar. Jump, fight, use a special move. Get money by beating up bad guys, helping friendlies, selling items or fishing (yes, fishing). Get health potions by beating up bad guys, buying them, or making them from the worms you catch (or use the worms for fishing). The macabre detail keeps it interesting, though, for the most part.
Does This 
Jar Make Me Look Stupid?
While the graphics in Dead Head Fred aren't really anything special in the sense of being, say, mind-blowingly realistic, they have a definite appeal. Especially if you like things a little on the ghoulish side. The character design is pretty stylish, though the colors tend to lean towards the slightly muddy (or maybe slimy). Everyone who worked on the art for this title must have a wicked side, and it lends a lot of character to the game. 
One might expect the music and voice-acting to complement the gothiness of the art, which would have been okay. Instead, there's an appealing disjuncture, with the characters having a distinct gangster movie sound. Perhaps "disjuncture" is too strong a word, though, as many of the characters do look like they came out of said gangster movie--if it had a head-on collision with a zombie flick.
All of this is really just a long way of saying that the sights and sounds of Dead Head Fred will appeal to some gamers, and turn off others. If you don't like this kind of design, you might want give the game a try anyway, because it really is fun.
Sticky, Repeat
There aren't very many perfect games out there, so it's no surprise (and not much of a criticism) to say that DHF isn't perfect, either. That said, I don't really have a whole lot to complain about.For some things, the controls seemed a little touchier or stickier than they needed to be. This was especially the case with Shrunken Head Fred. I leapt to my death quite a few times on a jump that shouldn't have been hard to make (but how many games have we had that happen in?).
The other small criticism I have is that once you figured out the best way to beat a particular enemy, ever other one of that kind became a sort of mechanical exercise. Throwing a whole crowd of familiar enemies at you at once did help in keeping down the tedium--fighting several at a time could require a different strategy than one on one. At times, though, I felt I was just going through the same series of button presses to get to the next area.
