\documentclass[tikz,border=10pt]{standalone}
                        \IfFileExists{newpxtext.sty}{\usepackage{newpxtext,newpxmath}}{}
                        \linespread{1.10}
                        \usetikzlibrary{shapes}
                        \usetikzlibrary{arrows.meta}
                        \usepackage{graphicx}

                        \begin{document}

                        % TikZ code with built-in styling for game trees
% TikZ libraries required for game trees
\usetikzlibrary{shapes}
\usetikzlibrary{arrows.meta}

% Style settings for game tree formatting
\tikzset{
    every node/.append style={font=\sffamily\itshape},
    every text node part/.append style={align=center},
    node distance=1.5mm,
    thick
}

% Built-in macro definitions for game tree drawing
\newdimen\ndiam
\ndiam1.5mm
\newdimen\sqwidth
\sqwidth1.6mm
\newdimen\spx
\spx.7mm
\newdimen\spy
\spy.5mm
\newdimen\paydown
\paydown2.5ex
\newdimen\treethickn
\treethickn1.0pt
\definecolor{chancecolor}{RGB}{117,145,56}
\definecolor{playeronecolor}{RGB}{234,51,35}
\colorlet{playertwocolor}{blue}
\colorlet{playerthreecolor}{orange}
\colorlet{playerfourcolor}{purple}
\colorlet{playerfivecolor}{cyan}
\colorlet{playersixcolor}{magenta}

% Game tree content from /home/docs/checkouts/readthedocs.org/user_builds/gambitproject/checkouts/913/catalog/journals/mor/vonstengelforges2008/fig9__Original_Layout.ef
\begin{tikzpicture}[scale=0.8
  , StealthFill/.tip={Stealth[line width=.7pt,inset=0pt,length=13pt,angle'=30]}]
% \draw [help lines, color=green] (-5,0) grid (5,-6);
\draw [line width=\treethickn,color=playeronecolor] (1.9,-7.625) arc(90:270:0.375)
  -- (5.6,-8.375) arc(-90:90:0.375) -- cycle;
\draw [line width=\treethickn,color=playeronecolor] (-3.5,-3.625) arc(90:270:0.375)
  -- (2.8,-4.375) arc(-90:90:0.375) -- cycle;
%% player 1 name 1
\def\playerone{1}
%% player 2 name 2
\def\playertwo{2}
%% level 0 node 1 player 0
\def\playerzero{Chance}
\draw [line width=\treethickn] (0,-0)
   ;
%% level 2 node 1 player 2 xshift -a=3.5 from 0,1 move \frac{1}{3}
\draw [line width=\treethickn,color=chancecolor] (-3.5,-2)
   -- (0,-0);
\draw (-1.75,-1) node[left,xshift=-1mm,color=chancecolor] {$\frac{1}{3}$\strut};
%% level 2 node 2 player 2 xshift -0.2 from 0,1 move \frac{1}{3}
\draw [line width=\treethickn,color=chancecolor] (-0.2,-2)
   -- (0,-0);
\draw (-0.1,-1) node[left,xshift=-1mm,color=chancecolor] {$\frac{1}{3}$\strut};
%% level 2 node 3 player 2 xshift a from 0,1 move \frac{1}{3}
\draw [line width=\treethickn,color=chancecolor] (3.5,-2)
   -- (0,-0);
\draw (1.75,-1) node[right,xshift=1mm,color=chancecolor] {$\frac{1}{3}$\strut};
%% level 4 node 1 xshift 0 from 2,1 move x
\draw [line width=\treethickn,color=playertwocolor] (-3.5,-4)
   -- (-3.5,-2);
\draw (-3.5,-3) node[left,xshift=-0.5mm,color=playertwocolor] {x\strut};
%% level 4 node 2 xshift -b=.7 from 2,2 move -x
\draw [line width=\treethickn,color=playertwocolor] (-0.9,-4)
   -- (-0.2,-2);
\draw (-0.55,-3) node[left,xshift=-0.5mm,color=playertwocolor] {-x\strut};
%% level 8 node 1 xshift 3b from 2,2 move y
\draw [line width=\treethickn,color=playertwocolor] (1.9,-8)
   -- (-0.2,-2);
\draw (0.15,-3) node[right,xshift=0.5mm,color=playertwocolor] {y\strut};
%% level 6 node 1 xshift -c=.65 from 4,1 move x payoffs 1 1
\draw [line width=\treethickn,color=playeronecolor] (-4.15,-6)
   node[below,yshift=0.1\paydown,color=playeronecolor] {$\mathsf{1}\strut$}
   node[below,yshift=-0.9\paydown,color=playertwocolor] {$\mathsf{1}\strut$}
   -- (-3.5,-4);
\draw (-3.825,-5) node[left,xshift=-0.5mm,color=playeronecolor] {x\strut};
%% level 6 node 2 xshift c from 4,1 move -x payoffs 0 0
\draw [line width=\treethickn,color=playeronecolor] (-2.85,-6)
   node[below,yshift=0.1\paydown,color=playeronecolor] {$\mathsf{0}\strut$}
   node[below,yshift=-0.9\paydown,color=playertwocolor] {$\mathsf{0}\strut$}
   -- (-3.5,-4);
\draw (-3.175,-5) node[right,xshift=0.5mm,color=playeronecolor] {-x\strut};
%% level 6 node 3 xshift -c from 4,2 move x payoffs 0 0
\draw [line width=\treethickn,color=playeronecolor] (-1.55,-6)
   node[below,yshift=0.1\paydown,color=playeronecolor] {$\mathsf{0}\strut$}
   node[below,yshift=-0.9\paydown,color=playertwocolor] {$\mathsf{0}\strut$}
   -- (-0.9,-4);
\draw (-1.225,-5) node[left,xshift=-0.5mm,color=playeronecolor] {x\strut};
%% level 6 node 4 xshift c from 4,2 move -x payoffs 1 1
\draw [line width=\treethickn,color=playeronecolor] (-0.25,-6)
   node[below,yshift=0.1\paydown,color=playeronecolor] {$\mathsf{1}\strut$}
   node[below,yshift=-0.9\paydown,color=playertwocolor] {$\mathsf{1}\strut$}
   -- (-0.9,-4);
\draw (-0.575,-5) node[right,xshift=0.5mm,color=playeronecolor] {-x\strut};
%% level 10 node 1 xshift -c from 8,1 move y payoffs 1 1
\draw [line width=\treethickn,color=playeronecolor] (1.25,-10)
   node[below,yshift=0.1\paydown,color=playeronecolor] {$\mathsf{1}\strut$}
   node[below,yshift=-0.9\paydown,color=playertwocolor] {$\mathsf{1}\strut$}
   -- (1.9,-8);
\draw (1.575,-9) node[left,xshift=-0.5mm,color=playeronecolor] {y\strut};
%% level 10 node 2 xshift c from 8,1 move -y payoffs 0 0
\draw [line width=\treethickn,color=playeronecolor] (2.55,-10)
   node[below,yshift=0.1\paydown,color=playeronecolor] {$\mathsf{0}\strut$}
   node[below,yshift=-0.9\paydown,color=playertwocolor] {$\mathsf{0}\strut$}
   -- (1.9,-8);
\draw (2.225,-9) node[right,xshift=0.5mm,color=playeronecolor] {-y\strut};
%% level 4 node 3 xshift -b from 2,3 move -x
\draw [line width=\treethickn,color=playertwocolor] (2.8,-4)
   -- (3.5,-2);
\draw (3.15,-3) node[left,xshift=-0.5mm,color=playertwocolor] {-x\strut};
%% level 8 node 2 xshift 3b from 2,3 move -y
\draw [line width=\treethickn,color=playertwocolor] (5.6,-8)
   -- (3.5,-2);
\draw (3.85,-3) node[right,xshift=0.5mm,color=playertwocolor] {-y\strut};
%% level 6 node 5 xshift -c from 4,3 move x payoffs 0 0
\draw [line width=\treethickn,color=playeronecolor] (2.15,-6)
   node[below,yshift=0.1\paydown,color=playeronecolor] {$\mathsf{0}\strut$}
   node[below,yshift=-0.9\paydown,color=playertwocolor] {$\mathsf{0}\strut$}
   -- (2.8,-4);
\draw (2.475,-5) node[left,xshift=-0.5mm,color=playeronecolor] {x\strut};
%% level 6 node 6 xshift c from 4,3 move -x payoffs 1 1
\draw [line width=\treethickn,color=playeronecolor] (3.45,-6)
   node[below,yshift=0.1\paydown,color=playeronecolor] {$\mathsf{1}\strut$}
   node[below,yshift=-0.9\paydown,color=playertwocolor] {$\mathsf{1}\strut$}
   -- (2.8,-4);
\draw (3.125,-5) node[right,xshift=0.5mm,color=playeronecolor] {-x\strut};
%% level 10 node 3 xshift -c from 8,2 move y payoffs 0 0
\draw [line width=\treethickn,color=playeronecolor] (4.95,-10)
   node[below,yshift=0.1\paydown,color=playeronecolor] {$\mathsf{0}\strut$}
   node[below,yshift=-0.9\paydown,color=playertwocolor] {$\mathsf{0}\strut$}
   -- (5.6,-8);
\draw (5.275,-9) node[left,xshift=-0.5mm,color=playeronecolor] {y\strut};
%% level 10 node 4 xshift c from 8,2 move -y payoffs 1 1
\draw [line width=\treethickn,color=playeronecolor] (6.25,-10)
   node[below,yshift=0.1\paydown,color=playeronecolor] {$\mathsf{1}\strut$}
   node[below,yshift=-0.9\paydown,color=playertwocolor] {$\mathsf{1}\strut$}
   -- (5.6,-8);
\draw (5.925,-9) node[right,xshift=0.5mm,color=playeronecolor] {-y\strut};
%% iset 8,1 8,2 player 1
%% iset 4,1 4,2 4,3 player 1
\node[inner sep=0pt,minimum size=\sqwidth,draw=chancecolor,fill=chancecolor,shape=rectangle] at (0,-0) {};
\node[inner sep=0pt,minimum size=\ndiam,draw=playertwocolor,fill=playertwocolor,shape=circle] at (-3.5,-2) {};
\node[inner sep=0pt,minimum size=\ndiam,draw=playertwocolor,fill=playertwocolor,shape=circle] at (-0.2,-2) {};
\node[inner sep=0pt,minimum size=\ndiam,draw=playertwocolor,fill=playertwocolor,shape=circle] at (3.5,-2) {};
\node[inner sep=0pt,minimum size=\ndiam,draw=playeronecolor,fill=playeronecolor,shape=circle] at (-3.5,-4) {};
\node[inner sep=0pt,minimum size=\ndiam,draw=playeronecolor,fill=playeronecolor,shape=circle] at (-0.9,-4) {};
\node[inner sep=0pt,minimum size=\ndiam,draw=playeronecolor,fill=playeronecolor,shape=circle] at (1.9,-8) {};
\node[inner sep=0pt,minimum size=\ndiam,draw=playeronecolor,fill=playeronecolor,shape=circle] at (2.8,-4) {};
\node[inner sep=0pt,minimum size=\ndiam,draw=playeronecolor,fill=playeronecolor,shape=circle] at (5.6,-8) {};

% Player color legend
\begin{scope}[scale=1,shift={(-5.65,-0.0)}]
\node[inner sep=0pt,minimum size=\sqwidth,draw=chancecolor,fill=chancecolor,shape=rectangle] at (0,0) {};
\node[anchor=west] at (0.3,0) {Chance};
\node[inner sep=0pt,minimum size=\ndiam,draw=playeronecolor,fill=playeronecolor,shape=circle] at (0,-0.625) {};
\node[anchor=west] at (0.3,-0.625) {1};
\node[inner sep=0pt,minimum size=\ndiam,draw=playertwocolor,fill=playertwocolor,shape=circle] at (0,-1.25) {};
\node[anchor=west] at (0.3,-1.25) {2};
\end{scope}

\end{tikzpicture}

                        \end{document}