\[ \boxed { {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) ={\frac {x \left ( -{x}^{2}+2\,{x}^{2}y \left ( x \right ) -2\,{x}^{4}+1 \right ) }{y \left ( x \right ) -{x}^{2}}}=0} \]
Mathematica: cpu = 0.032004 (sec), leaf count = 32 \[ \left \{\left \{y(x)\to \frac {1}{2} \left (W\left (-e^{c_1+x^4-2 x^2-1}\right )+1\right )+x^2\right \}\right \} \]
Maple: cpu = 0.062 (sec), leaf count = 27 \[ \left \{ y \left ( x \right ) ={x}^{2}+{\frac {1}{2}{\it lambertW} \left ( -2\,{\frac {{{\rm e}^{{x}^{4}}}{\it \_C1}\,{{\rm e}^{-1}}}{ \left ( {{\rm e}^{{x}^{2}}} \right ) ^{2}}} \right ) }+{\frac {1}{2}} \right \} \]