Because Wikipedia gives better overviews than I do:
Borderlands features four player online cooperative play, which allows players to join and leave games whenever they want to, along with other single-player and multiplayer modes and a large number of weapons. Players can choose from four different playable characters who each have their own unique abilities and skill trees. In addition, players may have access to customizable vehicles for "vehicular combat" and will also be able to customize their pre-selected character. Defeated enemies will sometimes drop equipment, which is then available for players to pick up. The game is described by Gearbox Software as an "RPS," or "role-playing shooter."Visuals:
While I didn't spend much time following the development or previews related to Borderlands before its completion, some controversy about the direction of the graphics and art style did come up around the gaming community during its development. The original art style was a bit more standard and gritty but was updated part of the way through the production cycle to have a more cell-shaded and cartoony feel by the time it was actually released.
In Borderlands final state, the colors are bright, the world is vibrant and both friendly and enemy character models are very nicely detailed. Textures on the XBox 360 become a little bit muddled as you get up to point blank range on your targets but in general everything looks sharp and the style come across as very unique and pleasing to the eyes. Perhaps the only big gripe with the cell-shaded style is that it occasionally becomes difficult to perceive depth or distinguish different pieces of terrain during a fast moving encounter but these incidents are far from game breaking and may be have been partially related to my level of intoxication.
In addition to the terrain and character models being visualized well, the guns and other weaponry are impressive looking and varied. Every weapon you pick up will differ in its model, color, scope, muzzle flash and a number of other visual elements. In comparison to other loot-centric games where "Joe's Long Sword +3" looks identical to "Fred's Short Sword +5" virtually everything you pick up in Borderlands is going to have some graphical element that distinguishes it and accurately reflects it's capabilities, even down to the number of barrels your friends can see when they look at the front of your badass new shotgun.
The sound effects and dialogue in Borderlands could certainly be seen as one of its brightest spots. Weapons and explosions generally add a great feel to the combat and I was especially fond of one specific sound effect that plays when you fire missiles out of the games vehicles. Additionally, player and NPC dialogue is done well and much of it is has a great sense of humor that matches the "gritty-but-silly" feel that the visuals also convey. You will never know what truly hilarious combat is like until you are listening to one of your friends yelling next to your ear by using the Berserk ability as you fire a shotgun into the face of a screaming midget.
At its core, the Borderlands gameplay is easy to get into and very satisfying. Jump in with your friends, activate a quest, kill everything in your path on the way to the objective and bask in the loot and experience you gain as you move along. It is a tried and true formula that has worked for Diablo, Titan Quest and a number of other games. Most interestingly is the fact that Borderlands begins to give you that familiar feeling of playing a MMO as you progress further and further along. Moving around from lower level zone to higher level zone, completing quests with your friends, leveling up and assigning talent points to your character. It all feels very familiar. Gearbox even blatantly ripped off World of Warcrafts color scheme for items via the "White -> Green -> Blue -> Purple -> Orange" progression of item strength. Fortunately, it is here where the FPS elements come to the rescue and pull Borderlands out of the "been there, done that" quagmire that it nearly falls into. The unique guns and grenades and rocket launchers along with the real time twitch based combat does much to differentiate it from just any old fantasy action-RPG or even from MMO's such as World of Warcraft that it seems to want to emulate.
Regardless of this all, no RPG is going to succeed without interesting abilities that make you feel more powerful as you level and encouragement to continue questing to advance the story and obtain more levels and loot. In the same vein, no FPS is going to succeed without adequate focus on weapons that are responsive and feel right as well as interesting enemies and encounters that challenge without frustrating. So where does Borderlands fall in these categories? To generalize, the RPG leveling, talent and gear elements are fairly light and the story is downright forgettable. On the other hand, the FPS elements are satisfying and combat is exciting and well balanced (that is if you can ignore the ridiculous fact that running an enemy over in your car instantly kills them even if it would have taken considerably more effort via normal means). The overall success and satisfaction of the gameplay comes from the fact that Borderlands brings the unique addition of FPS combat into the action-RPG genre in a manner that melds very well and causes Borderlands to really become more than the sum of its parts.
The last thing to point out that will effect the game and your overall enjoyment is unfortunately a number of glitches and bugs that exist upon release. Gearbox is working hard to get out patches to fix issues related to talents that are not working properly, sound issues on consoles and even problems that cause all of your items and money to be deleted as you join your friends games. I ran into one of these glitches when my XBox 360 froze up during the games final cut scene. Because of the timing of the crash, the last boss no longer exists in my game but it did not register me as completing the game or even getting the final boss achievement. My character is now stuck in a permanent limbo where I cannot finish the games final quest. Gearbox is working on a fix but it is still obnoxious to know that so many serious issues made it through to release.
To be totally fair, it is hard to imagine playing Borderlands in any manner that is not multiplayer and it seems quite obvious that the game is balanced around more than one person playing at a time. Bosses feel like they are designed around having multiple players, many talents and abilities lend themselves to working with others and even the in game vehicles have seats for two players. The Berserker gets abilities that encourage him to tank for the group, the Soldier gets abilities that encourage him to heal and resupply and Sniper simply needs all those other people distracting for him so he can sit back and snipe without being mobbed. In some ways the classes are unrestricted as they can use and level up proficiencies with any weapon type but your combat effectiveness really begins to shine when you utilize some of the specializations and support abilities that is encouraged for each class.
It is due to this overwhelming design around multiplayer that I wonder why some pretty important things were omitted, most obviously is the ability to trade assets. Not being able to directly trade items is a little bit insecure but far from gamebreaking. You simply drop the items to trade on the ground and pick up what want but when playing with strangers who may have no inclination to share or play fairly it seems silly that there is absolutely no ability to set loot rules or roll for items. The biggest fubar is the fact that you cannot trade or give money! If your friend Johnny needs another $5000 to buy that awesome purple sniper rifle in the shop then it's just too damn bad because you cannot give him any of your hard earned cash. Why a game that is based around working together would leave out such simple and important cooperative capabilities is just bizarre.
Borderlands is a great hybrid of RPG and FPS ideas and mechanics that is unfortunately marred by some weird design decisions and a few nasty glitches/bugs. It is a hard game to recommend if you are going to be exploring the world of Pandora solo due to somewhat monotonous gameplay and a very forgettable story but with a friend or three it stands up there with Gears of War and Left 4 Dead as an extremely entertaining and satisfying co-op experience.