That should be said, that this is correct for MOST games on Desura, but not all. There is games, like Incursion or The Tower that still require installation via client.
But in most cases it lake said in previous post - Desura, not like Steam, allows to get games as standalone installer .
Ah, both of those are in alpha/beta. Apparently they make an exception for games still in development. Of course the devs can still upload a standalone version, but they're not required to.
The only other exception as far as I know is games that were signed before the standalone versions were added. They may add standalone downloads, but they don't have to if they don't want to. Only one dev I know of has actually refused to add a standalone version for that reason, the developer of [censored]*. He's a d**k though.
*decided against naming names.