Space Invaders in 17 Lines of Nostalgic Code

si.js

p=389;$=l=t=0;c=" _ ";
onkeydown=function(e){
    (k=e.which)==39?p++:k==37?p--:!l&&(l=p)
};
setInterval(function(){
    _="<pre>";l&&(l-=20)<0&&(l=0);
    for(i=0;i<400;i++){
        if(i%20==0)_+="\n";
        if(~b[n="indexOf"](l))b.splice(b[n](l),1),$+=25,l=0;
        if(~b[n](p))p=n,b=[],c="xxx";
        _+=i==p?"oIo":~b[n](i)?".#.":i==l&&l?" | ":c
    }
    document.body.innerHTML=_+="\nP "+$;
    for(i in b)b[i]+=t^0&&t%5e3==0?20:t%2e3==0?1:t%1e3==0&&(-1);
    t+=o
},o=50);
for(b=[],j=2;j<136;j+=2)b.push(j),j==14&&(j=41)||j==55&&(j=80)||j==94&&(j=121)