PlasmaNinja,
You have many wiring errors.
Have a look at the video again, particularly around the 5 minute mark.
The one thing not shown in the video is that pin 16 is on the left and pin 1 is on the right
of that drawing.
Wire up all the connections to the 16 pins on the header as shown in the video.
One thing that you may not know/understand is that power connections for the backlight
and the LCD are totally separate.
The backlight power lines appear to be soldered directly to the backlight connections
rather than to the A (LCD pin 15) and K pin (lcd pin 16) on the 16 pin header.
A potential side effect of this is that it may bypass the current limiting resistor.
If so, this will eventually damage the backlight.
There is also a strange wire connecting connecting D3 to K
(LCD pin 10 to LCD pin 16)
I am assuming that was supposed to be the R/W pin on the LCD.
If so it is using the wrong LCD pins.
--- bill