Dirty Bomb is a shooter game made by Splash Damage.
It is free on Steam Store
Splash Damage stopped making updates for the game but still keep the servers in order.

About the game
The game is very similar to CS:GO, you have a primary weapon,secondary and melee weapon, but what makes this game different are the heroes.
There are more than 20 characters in the game which are called the mercenaries (mercs) which have unique skills and weapons.
Each Merc has been placed into one of these classes: Objective Specialist, Fire Support, Medic, Assault, or Recon.

Dirty Bomb is a more team based game than CS:GO, you can revive your downed friend and going 1v2 or 3 is way harder.
There are 3 game modes:Objective mode in which the goal is like the name says is to complete all objectives if you are attacking before the time runs out if you are unable to do that the defending team wins
Stopwatch mode is similar but this time 2 rounds are played, one round you are defending and the other one you are attacking.
Execution mode attackers can win by planting the C-4 or killing the enemy team, defenders win by defusing the C-4 and also by killing the enemy.

Loadout Cards
Are used for you to improve you mercs.
Loadout Cards come in 8 forms:Lead, Iron, Bronze, Silver, Gold, Cobalt and and Obsidian.
Each Loadout cards gives your Merc an augmentation which improves it. Max number of augmentation is 3, lead gives you 1, iron gives you 2, silver gives you 3 like every tier above it. The only difference is that higher rarity gives you a cosmetic change to your mercs and weapons.
Some of these augmentations can be: reload speed increase,more medpacks and ammo to use.

Abilities
Like I said each merc has an ability for its own class, some of those abilities are
Fire Support : Air strike (Calls in an air strike dealing massive damage)
Medics : Healing station (Heals allies in its radius)
Assualt: Frag grenade (You throw a frag grenade, that's it)
Recon : Refractive Armor (Makes you hard to see but not invisible)

Some general tips:
1. Like in CS:GO you run faster with your melee weapon equipped.
2.Finish downed enemies as they can be revived and healed by their medics.
3.If you have 2 or 3 friends downed you should heal your medic as he heals faster.
4.Aim for the head (I know like in every game but still)

My opinion about the game!!!
The game is fun,interesting and creative, each merc feels different especially when you make a good loadout.
Games are balanced and most of the time you are playing against player of your level even if someone leaves you can change teams or try t balance the teams again by using the ''teams by skill'' option.
I'm really sad the game is not being developed anymore but the developers said it's too expensive, but I'm still glad there are official servers which will still be optimized.