This is just some info, if you change the level of gameplay to Easy it actually makes the combo moves easier.
As for finding the game its self, the second time you are running through the mall with Riley you will go past the merry-go-round and up to the 2nd floor of the mall/shopping centre. Just as you reach the top the arcade is right in front of you, there are only 2 playable games both giving you a trophy.
The other is
(Played Jak X Combat Racing)
You just walk up to the back left corner of the game arcade and press triangle and that's it, you get the trophy but for Angel Knives it is like you are actually playing a game of Street Fighter or MK etc . If you just want to go for the trophy play on easy and the moves are made much easier.
I am not sure if you need to play this to get the difficulty trophies other wise you can just set it to easy and go for it and skip playing it when doing your harder runs of the game but if it does need to be played for them I find the best way to do it is by memory so you could use your share button and save the clip letting you watch the video on which ever level you are playing on and practice along with the button combos at the same time until you have them memorised 100% then go play the game.
The chapter is Left Behind> Fun and Games
When you go to actually play, if you do mess up at any time hit options then restart encounter and it will bring you back to the start of the fight giving you as much chances as you want instead of having to keep starting the chapter all over again.
Good luck as even normal gets a tad tricky at the end.