now this aint just a selfish request from linux user but more of a general hint what you really should push for in my oppinion. i guess you are aware that one of your major concerns is how your product can be set apart from the huge failures of the past (shootmania, nexuiz) and also the projects that dont deserve that label but still are close to non-existant (warsow, xonotic, cube 2, openarena .. the list is endless)

to be honest at this point i have little idea why i would pick your product over - lets say warsow and xonotic which are both open source, free 2 play and available on all 3 major pc platforms. and if i was you i would ask myself the same thing; what can i do better than those projects, what are they missing?

the answer in my opinion is easy access + marketing. with easy access i mean quakelive style serverbrowsers and easy joining without version conflicts (which is actually the only reason why we all started to play this instead of its technically superiour predecessor). it also means having your friends join you - which was easy for quakelive as everyone just switched over but next to impossible for newstarters (the steamcommunity can somewhat make up for that tho). marketing on the other hand can be done by going to steam alone. you could easily ride on the current indie-game hype by offering a low cost early access product that is available on multiplatforms (which steam strongly supports, pushing for their upcoming steamOS release).

so in conclusion i wouldnt invest in map variety, textures, animations and overall content so much right now but instead in bringing it to steam and having people talk about it. i would focus on having a multiOS client ready and stable even if there were only 3 basic maps to jump around in with placeholder textures and some basic weapons. then i'd go for an early access beta, reinvest some of the money you got from optimistic supporters into faceit or whoever to host a small cup for you.

get the ball rolling, no one needs another "well done & dead shooter"