I can see your on a negative rampage today from your other comments in this post. Take your own advice and play the game. Go into rumble with your friends if need be. Splash kills with combustion are rare. The kill radius is much smaller than hammer. The radius might be the same size as far taking any sort of damage, but the medium and outer edges of damage are very low. You have to be practically on top of the GG victim to be killed with combustion. With hammer the center and medium distances are kills and the outer edge takes big damage if they survive. Also the hammer has no delay on the explosion while combustion the delay is noticeable.