You forgot the part where after battling through the entire asteroid field, they find their Nemesis. But right before pulling the trigger on that final fucking asteroid that killed their mother, the ship's laser juice runs out. So the brothers have to go out and blow that shit up mano-a-mano, fuck YEAH! To bring home the poignancy of this last confrontation of their nemesis, they use the VERY SAME NUKE that dear old ma used to threaten them with (in a loving way of course) if they didn't eat all their peas.
One brother will nearly back out, not wanting to part with the last family memento, but the other brother will shout very meaningfully, "Let's DO this!"
Through heavy tears, Brother 1 will set the timer, yell, "GO GO GO!" and they'll race back to the ship while the asteroid looms menacingly. Brother 2, in the excitement, will flood the engine while trying to get it started. Brother 1, having years of experience with shitty farm equipment will pull wires out of random control panels and hotwire the SHIT out of that spacecraft. They'll then blast off just in time to outrun the nuclear explosion that first engulfs them, then spits them out, a bit scorched, but otherwise fine. "WOOOOOOOOOOOOOOOOOOOOOOOOOOOO!!!!!!!!!!!!!!!!!!!!!!"
They'll hug, Brother 2 will say, "Let's go back to the farm, little bro, I've had enough excitement for 2 lives!"
Meanwhile...
In darkest space...
A still large part of the asteroid that didn't get blown to shit tumbles....
tumbles....
TUMBLES... Across the screen.
[Fade to black]