Urban Terror has a normal assortment of guns. There are a variety of small, medium and large maps. Servers are run by the community so custom maps are not unheard of. All standard game modes are included: free for all, death match, capture the flag, and more. Urban Terror has a perk/equipment system to equip armor, ammo, silencers etc. The most unique aspect is the gameplay, which allows you to jump on walls, do power slides, bleed and heal yourself and teammates.
This game is 100% free.