How is that done?

A standalone game?

You don't.

Snowy said:
A standalone game?

You don't.

http://e621.net/post/show/221408/animated-breast_expansion-canine-dog-drakemohkami-

I meant games like these. Flash games.

Ah.

You upload a Flash file the same way you upload a picture. Save it to your computer and upload as normal, or open the flash in its own window (check that the URL ends in .swf, if it doesn't, this won't work) and copy/paste that URL to the Source field in the upload page to upload by URL (works just like uploading an image by URL).

Download the .swf and upload it. Or use a link to the .swf. But to be safe you should probably download it, test it, then upload it to make sure it works.

It's not that complicated...

Also, it's impossible to upload a game with multiple parts such as Dragon Bride.

If you're not sure how to download the Flash file:
Look for a link directly to the game (remember, the direct link ends with .swf). Right click that, "save link as"(Chrome, possibly others)/"save target as"(most browsers, I think)/whatever your browser names that option.

If there is no such link: view the source (In most browsers, control+U, but I think Internet Explorer doesn't have a shortcut, so if you're using IE look for a View menu at the top), open the Find tool (control+F), and look for ".swf" (no quotes). This should get you at least one link, if there is more than one try each one until you find the game.

If that doesn't work, post a link in this thread and I'll see what I can do.

"Uploading A Downloadable Game"

We can see right away that uploading and downloadable factor out due to the commutative property. The proper title for this thread is thus:

A Game: How is that done?

Please show your work in the future.
B-

Uploading and downloading are not commutative. If they were, BitTorrent wouldn't work.

0 upload A download A = 2*A