SPCOL has additional attributes X,Y,W,H so change line 381 to
SPCOL SP,0,0,2,2,TRUE
Assuming your heart's origin is the top-left corner, this code means "from the point of origin (0,0), draw a 2 by 2 hitbox and enable (=make true of) scaling so that if your heart grows big, so will the hitbox".
Right now I'm testing what can I do with SmileBasic but I plan to do a roguelike game using the code of undertale bullet hell system to create custom weapons and custom behaviors for enemies.
By the way, What kind of game do you want to do? and What can you do to achieve that objective?
My game that I want to make is called Monterra and the world Beneath, and it's an RPG game, that also has a little bit of every game genre, like action adventure, first person shooter (for some of the battle parts of the game) ext. But I won't release any more info about the game unless your in on the project.
And to achieve my objective, I'm going to get a couple of guy's to help me with specific things in the game, like sprite animation, game physics, and (if possible) 3D animation. I'll be doing the story and sound, while other guy's will do what they specialize in most (like sprite animation, game physics ect.