To keep it from speeding up, fetch a copy of the page to your hard drive and edit it, then view it in your browser.
Search for the second occurrence of the word "speed". It's in a section that looks like this:
<font class="small">Code:</font><hr /><pre>function movenemies() {
gametime = gametime + 1
if (gametime >= 0 && gametime < 100) speed = 80;
else if (gametime >= 100 && gametime < 200) speed = 60;
else if (gametime >= 200 && gametime < 300) speed = 40;
else if (gametime >= 300 && gametime < 400) speed = 30;
else if (gametime >= 400 && gametime < 500) speed = 20;
else speed = 10;</pre><hr />
Comment out the "if" lines by putting a pair of slashes (//) before the text and add one line with "speed = 80;". Or make it "speed = 90;" to slow it down some (or "100" to slow it even more). Don't forget to terminate the line with a semi-colon.
Like this:
<font class="small">Code:</font><hr /><pre>function movenemies() {
gametime = gametime + 1
speed = 80;
//if (gametime >= 0 && gametime < 100) speed = 80;
//else if (gametime >= 100 && gametime < 200) speed = 60;
//else if (gametime >= 200 && gametime < 300) speed = 40;
//else if (gametime >= 300 && gametime < 400) speed = 30;
//else if (gametime >= 400 && gametime < 500) speed = 20;
//else speed = 10;
</pre><hr />
Alternatively, you could leave the speed increases uncommented-out but just increment each speed value by 10 or something. Every time the code passes through that routine it increments the "gametime" counter and that's what ramps up the speed.
I didn't look through the whole page so don't know if it's there or not, but it would be good for something like this game to time how long it takes to do some little thing, and use the result to tune the speed of the page accordingly so it would run the same everywhere.
A few years ago a friend ran a test of some relatively simple javascript, comparing the speed between the Linux and Windows versions of Netscape, and between the Windows version of Netscape and Internet Explorer. All on the same hardware, the order from fastest to slowest was the same as just mentioned. That was a few versions of everything ago, though. I don't know how they'd stack up now.
