Brings back a lot of memories, and creates some new ones
Story: This game is a parody of sorts in the genre, with lighthearted jokes and interesting baddies [A giant bat that attacks you with poop, A Dragon with a sock puppet just to name a few]. The story is that you are knight (or at least you start off as one, more later). Your kingdom has come under attack by an evil wizard who has stolen some magical crystal from the king as well as a bunch of princess' that you are tasked with saving, and ultimately confronting the wizard himself and a slew of different lackeys on the way.
Graphics: Its pretty much like you are playing a flash game. Alien Hominid fans will know whats up, and probably a lot of people familiar with newgrounds. It has an old-skool feel, 2d sidescroller beat em up. The characters all seem very rich and vibrant in detail and color, and the different powers and such that you can employ really light up the screen brilliantly, it is a very fun game to watch, and the graphics are pretty much how they should be for this type of game.
Gameplay: Beat em up as I said before. You can be any number of different characters, Most of which seem like slightly altered versions of the Core Crew: Blue Knight- with Ice based attacks, Red Knight- who uses lightning, Orange Knight- who wields fire, and Green Knight- who works the poison. Plus many others, whos tweaks are different enough to legitimately be a different character. That is of course, if you are heavy into using magic. Magic is one of the best mechanics about this game and can really add a lot of flavor and a hint of strategy when playing through. Using weapons is pretty standard between all characters though, there are a lot of different types of weapons you can find and earn, all with different a attribute boosts or negatives onto your character. The attributes themselves are pretty basic [Strength- Levels up your damage with weapons; Defense- Decreases the damage you take from enemy attacks; Magic- increases range and power of magic attacks, and increases magic bar; Agility- Increases range and power of arrows, also increase speed and jump]. You can usually beat the game no matter how you decide to stack, although I might suggest not trying to go all out agility first, arrows aren't really all their cracked up to be. The level cap I think is at 99 or 100, I haven't gotten quite that far with any of my characters, but you do max out your stats in the late 70's which can take you awhile to attain legitimately mind you. Battle mechanics are pretty simple, whether you want to go all out melee and juggle around enemies with the various combos you can do, or go all out magic and spam enemies with various elemental attacks, or fire waves of arrows and jump around like a madman with high agility; or maybe somewhere in between. Any way you play, the game is really fun to play, especially with friends. No matter if its all over xbox live, or everyone over at one place, it is a blast. 4 people on the screen all spamming attacks and jumping around can leave you wondering where the heck your guy is and what is going on, but not a big deal. You can beat the Normal playthrough in your early 20s or close to 30 by yourself, but on Insane mode, I've barely gotten past the first quarter of the game and I'm level 77. Insane mode is definitely a challenge for those willing to try, and friends are a must unless you're some sort of prodigy.
Online/Multiplayer: Besides the main game story, you can also play "all you can Quaff", which is a game where you basically have to eat a bunch of fruit before the other players, its basically like one of the Mario Party or "Insert shovelware here" type of minigames that just requires a lot of button mashing. You can also fight in arena matches against other players, which can be pretty fun, but many people that play online are very good at this point. And of course you can party up with either friends or randoms on Xbox live with up to 4 people. The community at this point is pretty good, not a whole lot of morons as far as I can tell. A warning however, you cannot play with two of the same characters in one game [ie your lvl 45 Orange Knight cannot play in the same game as your friends Lvl 33 orange knight], So having a couple higher level characters will make PUGing a lot more headache free. It is a popular game on XBLA and has a continually decent following of players online at most times at least for some Co-op action. All you can quaff and arena are a little barren sometimes.
All in all: There is a reason why this is one of the most played Xbox Live Arcade titles. It is a lot of fun for the casual or more hardcore player, offers a lot of throwbacks to older classic 4 player Knights and magic action you might have loved when you were younger (Gauntlet anyone?) and manages to keep you hooked for a long time, it's one of those games that you can pick up and put down constantly over time, without having to spend time re learning the mechanics. A definite BUY for anyone.