I loved this ep, where to start!
The flashbacks were good, I loved seeing Shado again, shame she was only an hallucination. Now Ollie has confessed I wonder how that will pan out.
The return of Roy and The Calculator is instantly one of my fav storylines the show has done. From the first heist where Thea fainted, to Ollie chasing him in that awesome parkour sequence, the fight at Palmer tech where Felicity spotted the retinal tech to her keyboard showdown with The Calculator, just some of the best stuff the show has done IMO.
It also had good arcs for Felicity with her presentation and for Thea as she made her choice and sorted out the emotional position she is in with Ollie and Roy, with both respecting her wishes, the scene with her and Roy saying goodbye was really nicely played.
There was also some good humour in the ep, Felicity's face when she explained the bomb's explosive capabilities was hilarious and Ollie's grin "Really?" when Roy said he couldn't believe Ollie shot him.
Then there was the Nyssa storyline that began, her escape was great but her meeting and sword fight with Katana was pure gold! I love this direction for her and hopefully they won't just kill Katana off like they did Waller.
The reveal of The Calculator being Felicity's father was known but still well done, I wonder if he knows Felicity is on the other end of the computer he battled.
The action in this ep was quality as well, from the 3 sequences I already mentioned, to Team Arrow taking on Calculators mercs and Roy's big escape shot.