As far as gameplay,
Fight Night 3 doesn't break too far away from previous installments. Instead, this is more of a refinement of what worked in previous games. This year's addition is the stun punch, which switches the game into a first-person mode. From here you can really see the amount of damage you’re inflicting on someone. Also introduced is the Flash KO punch, which is more or less a one-hit knockout punch – the trick is landing one. A KO punch is slower than other power punches, but is a nice "last ditch" move for when you need to change the fight's momentum quickly. The downside to always using power punches is the drain it puts on your fighter's stamina. Use them too much and you’ll become tired and an easy target for a quick KO.
Career mode doesn't really evolve that much from past games and is one of the game's few disappointments. Even with the addition of rivalries, much of the game still follows the same train-fight-train pattern. Your fighter's career is really just built on reaching certain milestones. Having a rival who will chase you down during your career and try to put a snag in your rise to the top is a great idea, it just feels like it is an idea that is still in its infancy and needs more time to mature.
Training is handled through a series of mini-games. Before a fight you can train your fighter in one of three game types, each focusing on a different stat type. Some improve speed while others improve strength. All of the games are simple and revolve around timing or patterns. It takes some time to get the full benefit from each regimen, but in the end it is worth it. As you move up in ranks, you can hire new trainers (including "The King" from the Burger King commercials) that will improve your stats even further.
Outside of Career mode, there are several other modes that should give you a lot to do. My favorite was the ESPN Classic matches that let you recreate classic matches from the past.
"Get in the Ring" is the only major addition to the PS3 mode. The mode plays exactly like others, only everything is viewed from a first-person perspective. As you absorb your opponent's punches, your vision starts to get blurry, which is a really cool effect (even if it means you are getting your ass handed to you). I'll be the first to admit that I thought the mode would go over about as well as the first-person football mode 2k tried, but I was wrong. Once you get over the shift in perspective, the mode is actually pretty fun and one of the things that kept me playing the game longer that I thought I would. The first-person perspective is available in all modes, including online.
Fight Night 3 features a full-fledged online mode as well. Matches are easy to find and set-up, though the lobby system could use some work. Both ranked and unranked matches are available, as are leaderboards and the ability to take your created boxer online. Fight Night 3 also features ESPN integration while online that keeps you up to date on scores and sports news.