Like Bonkuts said, its only 4 megs, for a game with multiple routes and quite large sprites, thats not allot to work with...remember, SplatterHouse 2 is 8 megs, it definitely doesn't seem twice the meg count to me.
What Splatterhouse does better than most back then, is physics, swinging and splattering a zombie against a wall,or feel the recoil of the shotgun as you blow an enemy to pieces, fire the shotgun while jumping and you will be forced back by the recoil...sadly, splatterhouse 2 losses most of this.