I definitely prefer the second sprite. Both are pretty well executed and there isn't much to say about that.
But if I look at the flying enemy and the background it seems that the whole game looks more cartoony and graphical than realistic. The second's sprite face with eyes provides much more character and possibilities to bring in fun expressions - I don't played the original game though.
I have to say that the smoke looks from the gr<adient better in the first screen and from the overall contrast better in the second screen, although it's imo to bright for that kind of smoke.
I hope you finish this, looks like something I want to play
