After blasting my way through this achievement, I am happy to say I believe there is method to this madness!!! Keep your eyes out for the quips that characters say, it may or may not help you find out their next move.
I marked down the percentages of each possibility over 50 games:
Rock – 42%
Paper – 38%
Scissors – 20%
Your best starting move is paper. This starts you off with 42% for a win or 38% for a draw.
I noticed children and Lucy were more likely to start with scissors. Use rock as your first move when playing against them. I also noticed that if a character started with rock, their second move was often paper. Paper -> Scissors did me good.
‘Guess What I’m Doing Next’
72% – Same as previous move
28% – Different to previous move
This one was one of the ways I was able to keep a 3:0 streak.
For example, the enemy just played paper then said: ‘Guess what I’m doing next’. They are most likely to play paper again which gives me a 72% win rate when choosing scissors.
‘I’m Going To Play ______’
52% – Lie
48% – Truth
The best bet against this one is to play what they say they are going to play.
‘I’m going to play scissors’ – Playing scissors gives you a 48% draw rate, but also gives you a 26% win rate.
‘I Can’t Lose Next Turn’
58% – Plays the move that would beat your last move
42% – Plays a different move
Characters appeared to play the move that would have beaten your last move when saying this.
For example, you previously played scissors and they played paper. They say ‘I can’t lose this turn’ meaning they will use rock to beat your previous scissors. Play rock in hopes for a 58% draw or a 26% win rate.