HTML5 Canvas Example

HTML

<canvas id="canvas" width="640" height="400"></canvas>
<img src="http://image.dosgamesarchive.com/screenshots/WOLF-06.png" id="screenshot" />

CSS

#screenshot {
  display: none;
}

JavaScript

var xx = [126,303,166,272,157,220,159,133,25,298,188,176,208,91,289,283,269,167,211,106,88,213,19,28,
173,204,58,310,192,291,225,57,12,181,315,24,119,199,190,319,37,198,11,160,287,232,16,273,153,97,128,
84,277,271,114,212,226,61,138,142,201,302,197,81,10,49,2,62,205,42,27,134,89,312,163,75,246,248,295,
307,221,108,177,228,264,241,316,18,297,243,34,280,55,94,79,196,60,132,9,145,279,146,275,256,281,140,
41,304,194,162,30,40,122,50,270,253,255,282,26,268,121,250,21,109,286,317,149,261,17,165,214,217,305,
137,238,93,229,154,185,103,265,115,0,13,69,152,38,47,15,175,216,219,86,210,306,111,278,59,169,290,144,
96,200,117,20,70,8,48,63,67,66,124,259,65,288,156,263,73,136,83,141,242,262,193,237,182,299,301,170,
207,116,35,14,178,314,179,240,296,125,186,80,104,76,239,72,172,276,251,29,155,191,150,223,171,318,292,
92,222,31,244,52,54,158,308,98,74,164,113,257,143,85,174,227,224,206,230,53,100,266,202,148,90,187,
209,36,77,285,218,294,184,68,180,249,254,105,64,4,300,95,102,6,127,293,267,46,5,260,32,123,44,252,309,
247,129,231,33,284,135,3,233,45,43,110,56,120,168,234,131,258,22,236,139,274,78,71,311,161,51,101,203,
82,313,39,245,215,118,235,99,1,189,183,130,7,195,23,147,107,151,112,87];
var yy = [143,188,6,68,197,159,50,173,152,57,84,130,23,60,38,146,74,196,187,99,98,192,20,123,27,184,
141,179,193,180,88,168,182,101,191,7,53,172,11,79,117,69,144,83,148,157,134,51,3,87,120,135,78,147,
156,166,111,76,138,195,94,18,185,198,4,155,77,151,194,10,45,63,112,169,14,136,9,132,66,105,55,31,26,
171,114,34,142,154,127,167,73,16,39,67,170,72,15,107,149,122,12,102,183,41,90,37,158,161,2,113,104,
106,44,25,61,109,48,56,5,82,49,40,177,86,92,13,43,139,165,110,17,52,75,8,163,176,36,91,164,89,133,62,
115,30,181,178,128,1,189,21,186,160,140,116,175,125,96,85,71,42,28,108,100,24,137,22,119,46,58,95,0,
33,153,162,199,97,129,64,131,65,35,32,47,103,121,190,93,19,29,126,174,59,124,145,150,81,80,118,70,54];

function restart() {
  var d_canvas = document.getElementById('canvas');
  var context =...