Deadliest Warrior is a neat idea for a TV show and the idea, at least, translates into games reasonably well. The premise is that they're trying to accurately look at combatants over the years, from knights to ninjas, and determining which type of combat was the best. In the game, this translates into viking vs. apache, knight vs. samurai, or... yeah... pirate vs. ninja. It's a clever idea, but the mechanics of this high-damage fighting game don't lead to a lot of interesting depth, making it all fall flat.
The core of the fighting involves high, mid, and low attacks that combo together for short two-to-four hit strings. A stamina meter prevents you from just running up in your opponent's face and attacking forever, and every character has a limited number of projectiles (the ninja has stars, the pirate has muskets) that can be launched with the tap of a button. Attacks will occasionally lop off an arm, leg, or head, but even basic four-hit combos can deplete an opponent's entire life bar. To put it mildly, the rounds usually don't last very long, and it usually comes down to the player that made the first up-close mistake getting ripped apart.
That means that playing defense can be pretty important. There's a regular block that'll stop incoming attacks (though characters that don't have shields can't block projectiles), and you can combine that block with the attack buttons to attempt to parry incoming attacks. Guessing which height the opponent is attacking with isn't especially easy, but when you parry, the game slows down and gives you a free hit... which can completely end a match in many cases.
There's something cool about the violent and harsh nature of how Deadliest Warrior plays, but its quick rounds aren't especially satisfying. Part of this is the animation's fault, which makes the strikes look weak. And since the game slows down for a second to emphasize parries and round-ending strikes, it can be difficult to tell them apart.
There's an arcade mode and a few different ways to play offline, as well as a few online modes for ranked, unranked, and tournaments. There appear to be some serious issues with the online as of this writing, as the game typically doesn't connect me with another player when I attempt a quick match, and creating a match and letting someone eventually join usually ends with a "player has left the match" message as soon as the fight is finished loading up. Going through all of the player matching hassle for a couple of quick-death rounds makes it all feel like way more trouble than it's worth. Other issues include a versus screen bug that sometimes shows the apache, even though you're playing as the ninja. The whole thing feels a little amateurish in execution.
Deadliest Warrior isn't entirely without merit, as the speedy nature of the fights along with the constant dismemberments make it kind of funny. But the technical issues surroundng the action make the game's $10 asking price feel pretty steep. Even then, old games like Bushido Blade do this style of high-damage combat better.