Bloc is a Russian apartment block area, surrounding a courtyard. It is from the sniping mission in the campaign, in which you attempt to assassinate Zahkeav. This map is built for sniping or stealth, so it's time to get good at those aspects.
Stealth
To stealth around this map, there are a couple perks you will want. UAV jammer and dead silence are the two main perks you'll need. Dead silence is good because this map is so large, there will be times when it is quiet and you need to sneak up on a camping sniper. For perk slot one, it's up to you which perk you want, although I recommend three frags, or three special grenades. Next, you need to pick a gun with which you are most comfortable with the iron sights so you can pop a silencer on it. I suggest the P90 or MP5, although the G36C and AK-47 are also strong silenced weapons with decent iron sights and increased range.
Movement around this map is dangerous, and you must pick your route carefully. NEVER cut through the courtyard. You are left too exposed to enemy snipers and other enemy classes. Even if you have a smoke grenade, I do not recommend using it because it will just draw attention to you causing enemies to focus on the smoked area, or causing a grenade spam to be drawn into the smoke, usually rendering a quick death for you. Instead, go through the apartment buildings, and take the routes on the side. When turning corners, stop sprinting, and aim down the sights to avoid any delay in shooting if there is an enemy on the other side. Be cautious entering the apartment buildings as the enemy team will usually have a guard or claymores planted at entry-ways. Once you get inside, use your melee attack as much as possible to conserve ammo. At some point, you will be seen, but it's to late by then, you have the surprise element on your side. Finish off any enemies in the building with your silenced weapon. Repeat this cycle, running circles throughout the map, clearing out buildings as you go.
Sniping
Sniping requires a great deal of skill on Bloc, mostly because there are MANY places for an enemy to hide, and return fire at you from. You must always be alert to enemy snipers, and enemies equipped with stealth classes. You MUST have claymores as your first perk to prevent enemies from sneaking up on you. Also, the majority of players will have iron lungs as perk three to give extra breath holding time. Perk two is a tossup between UAV jammer (works good if a stealth enemy gets through the claymores, then you still have a chance to surprise them) or stopping power. This is all personal preference, as is the sniper rifle you choose for this level.
Setting up to snipe is fairly difficult as well. Make sure you set up your claymores so they are out of view, and unavoidable from enemies. Now in this level, it is highly recommended that you move after every 2-3 kills as enemy snipers will start to get a bearing on where you are hiding. Also, everytime you set up, make sure to scan all highly frequented sniper spots before getting too comfortable. Check the opposite building, and the stairs on the sides of buildings for enemies. Far too many times I have set up to snipe, and been picked off by an enemy I didn't even know was there. The rest is all personal experience and preferences. Some people like to snipe on the run, others like to hunker down and stay put while picking off enemies. That part is up to you.
One Last Tip
One less used way to play Bloc is with a shotgun. Use UAV jammer and dead silence. Use your knife as much as you can before letting loose the shotgun as it will give your position away. The tight quarters of the apartments are ideal for shotgun classes.
So that's the guide, should help you out with one of the more "annoying" maps to some people. If you learn how to play it, you'll soon be racking up big kill streaks. Have fun.
