making a game online?

i know how to make a game online but does the game need to be just for your internet browser or can you make a downloadable version of the game . could you still have patches ?

Fusionfall did this - there is a web version of the game and a downloadable standalone

I'm not sure how they managed patching for the standalone, but it's possible with either AssetBundles or a binary diff/patch tool (which is how most game patchers work)