Good Idea Dude!
SERIOUSLY! How come I've NEVER seen anyone come up with what seems to be such a SIMPLE but BAD-ASS-WICKEDLY AWESOME idea of a "methane gas powered flamethrower, fired from the palm!" Perhaps I'm just not ever looking in the right places if your not the first to come up with that... Idk. But Ah, I love this picture! Plus I love the Fallout 3 and F.O New Vegas games too, as I can see that your female character is wearing what looks like the leather outfit but only with a few slight variations which I like by the way, and also her knife looks like one of the knives from those games! Your fire also looks good too. Don't know why you'd be unsatisfied with it... It does look just like how fire should, after all, but if you're looking to improve it then one suggestion I'd give you would be to do a search on all sorts of unique but still realistic pictures of flames and study them a whole lot. Judging from the rather small flame in the picture though... you're flamethrower doesn't seem to be too effective... I think I would have made it bigger and start off at the base as a bright, white hot, concentrated beam of fire, maybe even spiraling in, a column that continues to expand wider the further out it goes. It should also fade off in brightness as it reaches its max range, become more puffy/fluffy towards the end but only if it's bigger than the one in the picture. Oh and also try making it flick up in tongs or maybe in puffy billows as the flame reaches the end depending on which of the two styles of flame you're in the mood for... after all, heat rises. If you want it to be really unusual, change up the color of the flame to be something unusual like crimson or green, or maybe you could even change it's characteristics too, like have it shoot somethin' a hollow ring of fire or perhaps it could spit big drop shaped fire bombs like some sort of grenade launcher but instead it shoots flaming blobs of pure fire that splashes and spreads out on impact!! For all we know she could be using any kind of combustible substance in that tank! In fact, perhaps the reason she's even wearing a gas mask could be because she's using some sort of poisonous combustible that produces noxious fumes and turns the flame green or somethin', whatever! Just let your imagination wander around when drawing!
By the way I like the whole futuristic sorceress sub-theme u got goin' with the hand flamethrower! That scores you creativity points!