JS1k: The JavaScript code golfing competition

for(_='(n+m)%_0,^^2>_5B*m,AAy+@00HH-12@G),F1,^7FE(d-J)D(b-I)R"#QFg.addColorStop(PP^QOL[NNi]Zc.YYfX++W=1V0]UMath.sT80H+(FXillFYca>v;Wv)Tin(n/=6^^^",Xc(m=2^?C(1H-3Ax"rgba(^?C(60-2AxStyle="Fg,0):_9e[3]=e[?():^Yca()	"P1,Q7H*-20+g=YcL(^for(function(i=0;i<L.length;Wi)3HOdff9cfYbaYarc(
u in c)c[u[U+[u[6]]]=c[u];a.widthV2H,a.height=4,SV,nVf="px Comic Sans MSC=t,l,i){Xont=t+f,Q373Xx("Ψl,i)},o=){return x=SW)*p,x-=0|x,0>x?-x:x},setInterval(){n=Wn>498?0:n,e=[q=Q542r=Qdddq,s=0)q,r,q,s],L=[12U,w=24^h=M=.95,x=4H,pV66^y=4F25350Off5f22
b=64H*14Fd=3240*12.5F572e3Ofd8aYsaveYscale(1,.3F
6H,p,7H,7,0Yrev=0;20{u=B?(NU+N6]+U):ue[i],Xc(x+u,y,Z,hFu+=Z;_99==88-1+4@27==66+5G25==44-34@43==33+7G40):B&&(NU-N6]-7]FZ*=M;x+=(w-(w*=M))/2,y-=--h,mW}"+(+2)-.05)+")166^5HFS=v=2;2H
IV2H*oJ=2*oETqrt(R*R+D*D)>50	;
34F62.5FEn>436	},30);';g=/[
-T-ZN-RD-H@-B^_]/.exec(_);)with(_.split(g))_=join(shift());eval(_)

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

a.width=1200;a.height=480;S=1;n=120;f="px Comic Sans MS";
C=function(a,b,d){c.font=a+f;c.fillStyle="#373";c.fillText("Ψ",b,d)}
R=function(){x=Math.sin(S++)*W;x-=x|0;return x<0?-x:x}

setInterval(function(){
  n=++n>498?0:n;

  K=[X="#542",Y="#ddd",X,Z="rgba(0,0,0,0)",X,Y,X,Z];
  L=[20,20,20,120,20,20,20];w=240;h=20;M=0.95;x=400;

  // Sky
  g=c.createLinearGradient(0,0,0,300);g.addColorStop(0,"#dff");g.addColorStop(1,"#9cf");
  c.fillStyle=g;
  c.fillRect(m=0,0,W=1660,y=480);

  // Sun
  g=c.createLinearGradient(0,250,0,350);g.addColorStop(0,"#ff5");g.addColorStop(1,"#f22");
  c.fillStyle=g;
  c.beginPath();
  c.arc(G=600+Math.sin(n/100+4)*400,H=300+Math.sin(n/100+2.5)*240,50,0,7);
  c.fill();
  c.closePath();

  // Ground
  g=c.createLinearGradient(0,0,0,2000);g.addColorStop(0,"#fd8");g.addColorStop(1,"#a80");
  c.fillStyle=g;//;
  c.save();c.scale(1,0.3);c.beginPath();
  c.arc(600,W,700,7,0);c.fill();
  c.closePath();c.restore();

  // Rails and cacti
  for(k=0;k<20;++k){
    j=0;
    if((n+m)%5<2){L[0]+=60;L[6]+=60;K[3]=K[0]}else{j=60}
    for(i=0;i<L.length;++i){c.fillStyle=K[i];c.fillRect(x+j,y,L[i],h);j+=L[i]}
    (n+m)%99==88?C(100-m*3,x-180+m*4,y+20):
    (n+m)%97==66?C(100-m*3,x+500-m*12,y+20):
    (n+m)%95==44?C(60-m*2,x-300+m*4,y+40):
    (n+m)%93==33?C(60-m*2,x+700-m*12,y+40):0;
    if((n+m)%5<2){L[0]-=60;L[6]-=60;K[3]=K[7]}
    for(i=0;i<L.length;++i){L[i]*=M}x+=(w-(w*=M))/2;y-=--h;m++;
  }

  // Shadow
  c.fillStyle="rgba(0,0,0,"+(Math.sin(n/80+2)-0.05)+")";
  c.fillRect(m=0,0,1660,500);

  // Stars
  for(S=k=2;k<200;++k){
    g=c.createLinearGradient(0,0,0,300);g.addColorStop(0,"#dff");g.addColorStop(1,"#9cf");
    c.fillStyle=g;
    c.beginPath();

    c.arc(I=R()*1200,J=R()*280,1,0,7);

    // Collision detection with sun
    Math.sqrt((G-I)*(G-I)+(H-J)*(H-J))>50?c.fill():0;
    
    c.closePath();
  }

  // Shooting star
  c.beginPath();
  c.arc(300+Math.sin(n/-20+4)*700,600+Math.sin(n/-20+2.5)*700,1,0,7);
  (n>436)?c.fill():0;
  c.closePath();

},30);