I'm liking how it is heavily indie focused, but I have some questions before I jump in.

Most of the games are stand alone installers right?
Some games require you to run the desura client in background (offline or online)?
And fewer only working via steam I've gathered?
Do some games require the desura client to all ways be on and online?

If only each game's page had more info on how it works, I would all ready be buying stuff there.

I'm browsing game pages now, and not one mention of drm or if it requires the desura client to run, or install.
I really hate blind buying.

yes.
yes, just to install a game then you can keep it offline. you could then just zip that directory as a file and threat it like a standalone installer.
yes.
no.

Great that helps. (can we give rep? or is rep similiar to post count or something?)
For the games that require the client, do I get some sort of warning those games require the client, BEFORE I BUY IT?
I want to back up my game installers. I've lost way too many harddrives (byebye PR0N)

Most of the games are stand alone installers right?
Yes.

Some games require you to run the desura client in background (offline or online)?
I don't use the client, at all. I just download the installers, like in GOG.

And fewer only working via steam I've gathered?
Yes, a few (just a few) games they sell require Steam.

Do some games require the desura client to all ways be on and online?
I don't know, I haven't found a game like that... yet.

the client is absolutly not a mandatory , worse it's bugged .

Just use direct links for each games, downside , it's a bit difficult to track down updates if you have lots of games there.

For some the client is mandatory. If you filled this in as a question, then you could have marked this as a solution thus giving someone 5 rep.
now you can only hit the + button.

It does not give any warning before buying, but i believe most games that you buy (if not all will have a standalone installer) its mostly for the free games that doesn't always have.
But as i said you can always zip any installed directory, thus making that your standalone installer.
It will however always warn you about steam before buying.

I have downloaded all my desura games (over 400) so i know what i am talking about ;) :p.

There is a trick that lets you check (before buying) whether a game will have a direct download. I think it involves manually constructing a link that the game's download would have, but I never tried it myself. Someone who uses Desura more than me might remember it better.

Good, cause I'm looking for some steam games, that have DRM-FREE alternative downloads.

I'm looking to get Knights of Pen and Paper +1 Edition DRM-FREE for my pc, and I don't think it excists.

ummm , i only tell from my experience , all games (18) i have there don't need it . I don't have a lot experience so i trust you.

That's correct, it doesn't exist.

Anyone happen to know if I can play the android/ipad version of KoPaP+1E on my pc somehow?
(I'm getting to far ahead of myself, these versions also probably have DRM of some kind, sigh)

If I can, they probably wont allow custom screen resolution right?

I believe there are some android/ipad emulators but i have no experience with those.
You could try it though.

If the game/application uses native code rather than being Java-only, it needs to be compiled for x86, which I'd guess few are. Google play store does, however, claim that Knights of Pen and Paper +1 is compatible with the Asus Eee 701 we have at work that I recently installed Android on (because good luck finding a GUI built for that resolution among desktop OSes). I'm not about to buy the game (much less on the work account), but that's some sign, at least, that it would run on any computer you can prod enough to accept Android.

Then again, both Firefox and Chrome claims to work as well, and the former refuses to accept that there's a connection available, while the latter doesn't even manage to show its start screen before it crashes (the built-in browser works a little while, and Dolphin is rock solid). But that might be partially due to the very low-end hardware, specifically the CPU and graphics.

In short: Android on x86 is very much an experiment.

I can't really answer the resolution question, but here's a link on how to run Android 4 Ice Cream Sandwich on a Windows 7 PC via VirtualBox.
If that's not helping, searching for "run Android on Windows" should bring up plenty of results.