The game seems to be a lot like D2, with custom item stats, crafting and all that.

Does the cash shop ruin the game? Do you have to use money to be able to enjoy the game fully?

cash shop not needed... Just more convenient (unless you want to upgrade weapons past+6 then you need cash shop - this is the only gamebreaker from cashshop, but is very expensive anyway)

minute away from finishing the download, my internet connection goes down for few mins and the download wont continue. God damn bad downloader if it downloads the game in parts but doesn't even bother to save them...

use the torrent method link provided on t3

worked 4 me, i had same problem with the regular download

lvl 6 MM atm.
Following this build:
http://www.hellgate-resurrection.de/index.php?module=cms&task=article&article=1717&sectionid=1&hgrchars=00000a0033a77aa50000000000001||en-marksman.html

And adding points to accuracy and stamina mainly. Keeping few spare points for strenght, if I find some good item that requires it.
Am I doin' it rite?

Yeah. Check out the market and see the requirements for the end-game items of your class.