One of the major drawbacks of there being so many quality open source games is that it's too easy to dismiss games that don't provide instant and accessible fun.
I'm just as guilty as anyone of this; if I download a game and there's so much as a whiff of having to compile or make anything then it's goodbye from me and onto the next game. Having a young son, I have very little time to play games, so anything that looks like it's going to cost me more time than it should gets discarded.
It's having this in mind that has caused me many a headache in trying to make Nuclear Graveyard instant and accessible. After I'd first completed it up to version 1.0, it had about 12 keys, like "shoot", "wait", "autofire", "guard" etc... A few comments from prospective players had informed me that this had understandably put them off, so I changed it to a menu system.
Unfortunately, I still don't think this has placated them. When you first run the game, it looks like an FPS, so I imagine a lot of players wonder why they can't run around and shoot stuff. (This is because of things like Action Points). I've tried putting big warning signs on the screen saying things like "Out of action points!", and other things to give people an idea of how it works. I just fear that in this day and age, they'll have gone onto another game before they get the idea. Maybe originality doesn't pay!