1. Collectibles
1.1. All ctOS Tower Locations
1.2. All ctOS Breaches
1.3. All QR Code Locations

2. Miscellaneous
2.1. Black Hat Trick – Kill 3 enemies with a single IED
2.2. Magic Smoke – Kill 4 enemies within a single instance of Focus
2.3. Free Radical – Escape a level 5 police chase
2.4. Scanproof – Escape a level 5 police scan

Clear Signals
Unlock every ctOS Tower
There are a total of 13 ctOS Towers in Watch Dogs. Finding all of them will reveal all collectible locations on your map and earn you the Clear Signals Trophy / Achievement. Each tower also unlocks a fast travel point.

You must hack ctOS systems to make the towers available. ctOS systems are always marked on your map from the beginning on. You can either hack them in free roam or wait until the story requires you to do so (you have to hack all of them to make it through the story anyway).
Once you have hacked the ctOS systems you can activate the towers. They are all on rooftops, so it requires some climbing and you must use your hacking skills. Use surveillance cameras to find little control boxes that open locked doors.

None of the towers are missable and you can still get them in free roam after beating the story. Because they reveal all collectibles and additional fast travel points you should get them as early as possible.

System Mangler
Complete every ctOS Breach
There are a total of 16 ctOS Breaches in Watch Dogs. Completing all of them will earn you the System Mangler Trophy / Achievement.

To unlock their locations you must activate all 13 ctOS towers. The ctOS Breaches are little side events in which you must hack 5 boxes within a certain time limit. You often have to climb up buildings or use surveillance cameras to reach them. In some cases you even need to place a vehicle in front of a wall and use it as a stair. You can start the breaches by hacking the first box.

As with all other side activities and collectibles you can still do this after beating the story.

Read-only
Complete the final mission in the QR Code Investigation
There are a total of 16 QR Code Locations and 1 QR Code Investigation Mission in Watch Dogs.
Finding all QR Codes will unlock the mission and completing the mission will earn you the Read-only Trophy / Achievement. You will also get a new weapon (Tommy Gun) as a reward. To reveal the code locations on your map you must unlock all ctOS towers. The displayed locations aren’t very accurate though and you must find one specific surveillance camera and look at the QR Code from a certain angle. The correct camera is sometimes far away, or can only be activated from an elevated position.

All Codes are saved automatically when you find them. None of them are missable and you can still get them in free roam after beating the story. They are also a requirement for the “They Call Him The Vigilante” Trophy and Achievement.

Black Hat Trick
Kill 3 enemies with a single IED
This can easily be done against the police. Simply shoot around on the street until someone calls the cops. Wait for them to arrive and try to hit 2 police cars with 1 IED. This works best if you trigger the IED before the cops leave their cars. There are always two officers in each car. The IED is an explosive device similar to C4 and can be bought at Tobias’s Shop for $300. You will unlock this shop automatically during the story and it can then be found in the south-western corner of the “The Loop” district.
You can also craft the IED in your weapon wheel if you have unlocked the respective crafting skill, find it during several missions, or get it from weapon trade investigations.

Should you fail to get this trophy / achievement you may reload the last autosave in the pause menu to get your IEDs back.

Magic Smoke
Kill 4 enemies within a single instance of Focus
To do this you must first acquire the “Focus” skill from the Combat skill tree. Also buy the respective upgrades if you can. They will make this much easier. Cops are easy targets to get this trophy / achievement. Shoot around until someone calls them. They usually send 3 cars, with 2 officers in each car. Aim at their windshield as they drive towards you, press the right stick to activate focus, and kill them as quickly as possible.

Reload the last autosave in the pause menu if it didn’t work the first time.

Free Radical
Escape a level 5 police chase
First off, you must build up your wanted level. Start shooting at civilians until someone calls the police. When the police arrives, go into a building (or on a rooftop) where you have a lot of cover. Kill the police reinforcements until your wanted level (see bottom right of the screen) is maxed out. This will only take a minute or two.
Now get into a vehicle and drive to a location where the cops cannot follow you. There is a really great spot for this in the very north of the “The Loop” district. Below the most northern street is a tunnel. At the western end of the tunnel is a room behind a gate. Go in here, close the gate and wait 2 minutes until the cops go away. Helicopters cannot see you here and the police cannot open the door for unexplainable reasons.

Scanproof
Escape a level 5 police scan
To trigger a level 5 police scan you must build up your wanted level. This can be done quickly by killing civilians. You can see your wanted level in the bottom right corner of the screen (grey square icons). Make sure that nobody calls the police before you reach the fifth wanted level! Civilians that are about to make a call have a red triangle above their head. Eliminate them quickly!

You should do this in a crowded, but open area where you can easily spot callers. The docks in the north-eastern corner of the map are great for this.

Once you hit wanted level 5, have someone call the cops. You will now see yellow circles on the map, these are the ctOS scans. To escape the scan you must drive to a distant location. Place a marker at the other end of the map and use a very fast vehicle. You should also apply the “Jam Coms” device. It will stop the ctOS scan for a short moment and buys you some time to get away.