I'm not sure I've seen them both...
WARNING: "I can only remember" spoilers below
"Tom Atkins sacrificing himself to save the day by blowing up the space slugs"
I meant the VERY end with the stupid dog bit.
And there's another (alternate) involving a graveyard or something.
But both add a
WARNING: ""CREEPS" ending" spoilers below
needlessly and annoyingly downbeat twist to the (basically light-hearted) film and thus also waste Atkin's noble sacrifice."