New Game Maker 8.1 Engine

[Jeff]

I'm not sure about the semi-solid blocks, I couldn't reproduce the problem.

Whenever Mario takes damage, the game freezes.
In obj_deadmario's creation event:

Code:

if (instance_exists(obj_parplayer))
{
    instance_create(obj_parplayer.x, obj_parplayer.y, obj_deadmario)
    alarm[0] = 1;
}

you're creating another instance of obj_deadmario, which creates another obj_deadmario and another, and this repeats forever. Or until GM realizes that it's stuck and crashes.

When I stomp a Galoomba, all of them disappear instead of just the one.
In scr_damage:

Code:

if (place_meeting(x, y + vsp, obj_parenemy)) && vsp > 0
{
    vsp += -10;
    with(obj_parenemy)
    {
        instance_destroy();
    }
}

you're destroying every instance of obj_parenemy. If you want to destroy only one, you'll need to get its id and destroy that. Something like this:

Code:

var enemyId;
enemyId = instance_place(x, y + vsp, obj_parenemy);
if (enemyId != -1 && vsp > 0)
{
    vsp += -10;
    with(enemyId)
    {
        instance_destroy();
    }
}