I have never played a game with such a good gameplay. It's hard for beginners but if you are an advanced player you will love it! The main gameplay element is jumping. The movement is very important as important as aiming. Just search for Urban Terror Frag Carousel on Youtube.
Gameplay is phenomenal, the movement takes a little getting used to (powersliding, wall jumping, bunny hopping) but after a few hours it gets easier, and after a few years it's second nature. The hit zones seem well outlined and I'm rarely left swearing blindly that I hit him, literally or figuratively take your pick. There is no offline, it's 100% multiplayer focused and this keeps it dynamic, a large selection of custom maps and servers keeps everything fresh, and the classic maps such as Turnpike/Casa/Uptown etc. seem well balanced.
It's a completely free game, and yeah the graphics take a hit but this doesn't remove from the enjoyability of it. Only Age of Empires II: The Conquerors has given me nearly as much fun, online or off.
Considering it is free, I suggest trying it regardless. Get used to the movement and weapon settings before you curse it as being unplayable, though.
Great gameplay, tons of servers everywhere... and awesome maps!
The items and weapons are balanced and fun!
If you get hit your stamina bar lower makes you slow, while bleeding makes aiming more difficult!
Get used to jump and dash, then you can actually see how good this game is!
Urban Terror is a realistic/modern-styled, multiplayer-only, first-person shooter that I certainly enjoy.
There is a learning curve, but nothing intimidating like Planetside 2 for example. (it'll be best to read a bit beforehand to get a feel for equipment, and also remapping the keys can be beneficial depending on you.)
It's weapons are based upon actual models for the most part and are overall well-balanced and all have their pros and cons. The loadout system is one of the best I have used, making me think about what I value most for a given scenario. (an extra gun means one less inventory space, "do I want a smoke grenade for cover or extra ammunition?" etc.)
Movement in-game can be wacky in that wall-jumping and other odd techniques for enhanced speed and mobility are available and offer a tactical advantage if you choose to learn them. You don't have to, but you'll certainly see them in action.
Graphics take a hit but given it's nature it's perfectly acceptable. You know it'll run well.
Gameplay is solid, with all the core FPS gametypes and a more granular damage system as well as a bleeding and bandaging mechanic. Maps are memorable as well.