None!

If you really want a hi-res Doomxen get a source port. Zdoom's a good start, but isn't faithful.

im a mac user, and zdoom OS X is well... it doesn't work. it exists, but is terrible.

no, what i mean is i want a way to increase the video mode's resolution, a lot of the games look like they've been shrunk down... you know that specific type of pixelation ya get when you make the screen size smaller with some fps games? (like when you press the - button and give it a border around the screen that you can increase the thickness of)

basically, im thinking they look like they are meant to be viewed larger, but are scaled down. how do i scale them up?

Look here, probably you find answer to your question
http://www.doomworld.com/classicdoom/ports/index.php
Hope it helps you.

Edit: You can use ZDoom for dos, or legacy for dos, Vavoom for dos you need CWSDPMI. And put your wad to source port folder. After running game you can change resolution.
OR use Legacy for MacOS
http://www.dosgamesonline.com/index/utilities.html
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The official Hexen for Mac demo distribution, about 11 MB in BinHex format.
ftp://ftp.idsoftware.com/idstuff/hexen/mac/MacHexenDemo.hqx
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But i even newer saw full hexen mac version, this exist?
I am extract resources from hexen mac version so images sprites etc looking better then pc version. Have more resolution of image.

basically, im thinking they look like they are meant to be viewed larger, but are scaled down. how do i scale them up?

output=opengl
fullresolution=0x0 # 0x0 stands for your desktop video mode
aspect=true