Firstly well done to Cas and more importantly Darly Powell; what an outstanding coach, never thought he deserved to be booted from Leeds and now he's showing his worth with another SL team, Cas fans should be very proud and rightfully so, they're game plan worked a treat... So what was it?

From what I could see not rocket science, but executed very well.
In def they arched the edges allowing their wing, centre SR to move upward when we looked to move the ball out wide, we don't play flat across the line but with dummy runners, with their edges pushing up Wigan were forced to play down the middle with no plan B (this issue has been raised before) when a team pushes up their edge defence the halves become afraid to move the ball out wide incase of an interception or hospital pass. Considering this I'm surprised Rocky wasn't brought on sooner, with his pace in the halves a 'show and go' might have caused their defence to be more hesitant when arching the edges.
This is one of the negatives when running such structured plays, yes we can interchange and slot in different players and they all will become cogs in the machine, but the opposition also know what's coming, Cas had the movement and skill to read and null our attack.

In attack cas moved the ball very well across our middle unit; once you move the ball across the middle unit the def on the edges has the slide, this is when the defence out wide is susceptible to being stretched, overlaps and falling victims of show and goes... Our middle unit at times looked too tight.

Ball strip over the line hasn't been a penalty try for many years. Consult a rule book if you can read one through those bitter tears.