Pinball FX3

You can still get the cannon unlocked with the skill shot. I just did it and it took me around twenty tries.

Anyway, here's the guide I wrote for the FX 2 version.

Before you launch the ball you will see on the Dot Matrix a target moving across the screen. You want to launch the ball as soon as you see the target over the robot. This will nab you a random bonus that will appear on the Dot Matrix. It will most likely take a lot of tries until you get the one that you want, but keep restarting the table until you get the Cannon Opened skill. You’ll know you got the correct one when you see a car driving away from a robot on the dot matrix. When you get the bonus, shoot the ball into the subway tunnel on the lower left of the table. The cannon will be loaded and fired at the robot, unlocking the achievement.

To those who prefer a video

This is recorded in FX2 but works exactly the same way in FX3 though it seems to have gotten a bit "harder" to get the right skillshot,I use the word Harder loosely as keep restarting until you get it, can't really be described as hard though time consuming. However it didn't take me more than 5-10mins to get this achievement so just keep shooting & it will pop...
A SMALL WARNING though,for me it did not write the words "Cannon Opened" but I assume this was do to the fact that I lost my ball before it appeared so just keep an eye out for the speeding car & don't fret if you immediately loose the ball afterwards cause the Cannon will remain open until you either hit it or have to start a new game so you have all 3 balls to try for this & it is quite easy

GUIDE:

- Launch the ball when the crosshair is in front of the giant robot in the Dot Matrix Screen found in the top left corner

- Keep Restarting the game until you get the Speeding Car followed by the words "Cannon Opened!" in the Dot Matrix screen
- After this you need to use the Right Flipper to get the ball in to the Cannon,do this by hitting the lane (marked by a Red Circle) that's located just below the fixed ball in the bottom left of the screen.

- NOTE:
The fixed ball is located in the lane that leads up to the blue UFO.
The Red Circle is also located in the left Drain Lane,so to specify it's the top Red Circle :)

- GOOD LUCK


(If any one would prefer a video recorded in FX3 instead then please let me know,saved my try on FX3 but since it didn't go as smooth as did (loosing the ball & that) I've decided to use this unless requested otherwise

Unlike the previous games, it appears that you can't get the proper mode just from launching the ball with a successful skillshot so this is what you have to do. You have to get the ball to roll down the far right inlane. When it's lit, it looks like 3 red rings, one inside the other. Once the ball goes down this lane that lights red and you need to hit the far right orbit. You have 10 seconds or so to do this, the red light will be lit up and the right orbit will light up kind of greenish and it says Right Tunnel. As long as both of those are lit you can still hit that lane.
If you are successful, that same red symbol will now be lit at the lower left sinkhole. Just hit that, and hit launch to fire at the robot and that's your achievement.