Horseback riding pops up now and again for both characters, and it's an enjoyable distraction from the usual trudging around that you do. Controlling the horse is initially a bit of a pain, but once you get used to it, it's both a quick way to get places and a fun way to engage in combat. There are a couple of scenes where you'll find yourself blasting away at other bandits on horseback. Aiming while on a horse is tough, but that makes sense.
Controls on the PC version of Call of Juarez are, as you might expect, significantly different than the 360 version's. Aiming is certainly simpler with the use of the mouse, and whip swinging is actually a little easier as well, as you don't have to fumble around with analog sticks. However, other mechanics are made a bit clumsier by this control scheme. Ray's concentration mode now requires you to press two buttons at once to holster his weapons, and horseback riding, which was already unwieldy to control, is even tougher to deal with on the PC. The crouch mechanic also needs some key remapping to be useful, as the key has to be held down while you move, and default setting of the CTRL key just isn't comfortable.
Another key difference between the PC and 360 versions of Call of Juarez is content. None of the extra missions or gun duels that the 360 version has as separate modes are present in the PC version. At least you still get the same 8- to 10-hour campaign, as well as the same multiplayer mode. LAN and online versions of the multiplayer are available, too. The multiplayer is pretty typical class-based FPS-style action. You can play as either a rifleman, a gunslinger, a sniper, or a miner, and there is a variety of modes like deathmatch, team deathmatch, capture the flag, VIP, and so on. The four classes are reasonably well balanced (though in skirmish modes, snipers seem to rule the roost), and there are enough different modes to keep the action interesting for a while. It helps that the game isn't kneecapped by bad weapons, as some historical FPSes tend to be in the multiplayer arena. All the weapons pack a nice punch, though each class is only assigned a pair of specific weapons, a primary and a secondary. There are no weapon pickups on the various maps. All told, the multiplayer isn't remarkable, but it can be fun.
In terms of presentation, Call of Juarez is all over the map, especially as far as graphics go. Environments are definitely the high point. As you wander around the game, you'll see tons of attractive Old West scenery, from mountain vistas to desert plains. It's great-looking stuff that's made better by some nice lighting effects and solid texture work (save for a few occasional ugly spots). On the other side of the coin are the character models. The people you encounter all have that sort of Doom 3 overly shiny thing going on, and they even look a bit mutated to boot. Animations tend to be stiff, clipping issues pop up quite often, and any time you catch a glimpse of what your own character model is doing, either in a reflection or a shadow, or just by looking down, you'd think you were controlling an animatronic robot from some ghost town tourist trap. Still, the problems are mostly outweighed by the positives, and the game as a whole looks good.
It looks noticeably better if you happen to have a video card that supports DirectX 10. On the higher resolutions, environmental details and grass/foliage are much denser and cleaner looking. Lighting and shadows are also more impressive. At the same time, even on a high-end PC, the game chugs a bit while running on the higher resolutions. It's nothing game breaking, but the frame rate drops quite a bit. It's also worth noting that on multiple test PCs, loading times for each chapter and multiplayer map were over the top.
Multiplayer is solid fun.
Audio is less scattershot. Apart from some great sound effects and a soundtrack that nicely captures the atmosphere of the era, the game has mostly solid, if slightly hammy voice acting for nearly all the characters. Billy is the only one who didn't fare very well, as the actor who plays him sound like he's in as big a rush as possible to get out of the recording booth, but pretty much everyone else is on their game and delivers an entertaining performance.
As ham-fisted and generic as Call of Juarez can be at times, it does enough right to transcend its various issues and turn in a pleasing shooter. It does the Old West motif well, the gunslinging (and bible slinging) are a lot of fun, and the capable multiplayer modes have enough going for them to give the game a bit of staying power. It doesn't quite rise past the ceiling established by other recent western shooters, but it's good, solid fun all around. That said, if you have the choice, you should probably look to the Xbox 360 version. The PC iteration is good, but its lack of content for its price tag and slightly dodgy DX10 support prevent it from being the ideal choice.