I want to learn game development as a hobby, and I think GameMaker is a very good engine for that.

I've been learning 3D perspectives in game maker, but I have a big problem. I've been using a 2D Sprite as the player object, but I need help trying to billboard the sprite so it faces the camera at all times.

obj_3d:

//Draw Event

var matrix = matrix_build(x, y, 1, 0, 0, 0, 1, 1, 1);
matrix_set(matrix_world, matrix);


draw_set_alpha(0.5);
draw_set_colour(c_black);
draw_circle(0, 0, sprite_width * 0.2, false);
draw_set_colour(c_white);
draw_set_alpha(1);

matrix = matrix_build(x, y, z, 90, 0, 0, 1, 1, 1);

matrix_set(matrix_world, matrix);

draw_sprite_ext(sprite_index, image_index, 0, 0, image_xscale, image_yscale, 0, image_blend, image_alpha);

matrix_set(matrix_world, matrix_build_identity());

obj_camera:

//Create Event

cam = camera_create_view(0, 0, res_w, res_h);
fov = -70;
zNear = 3;
zFar = 3000;
view_enabled = true;
view_visible[0] = true;
view_set_camera(0, cam);

proj_mat = matrix_build_projection_perspective_fov(fov, res_w/res_h, zNear, zFar);
camera_set_proj_mat(cam, proj_mat);

xFrom = x;
yFrom = y;
zFrom = 100;

xTo = 0;
yTo = 0;
zTo = 0;

gpu_set_ztestenable(true);
gpu_set_alphatestenable(true);
camera_dir = point_direction(xFrom, yFrom, xTo, yTo

//Pre-Draw Event

view_mat = matrix_build_lookat(xFrom, yFrom, zFrom, xTo, yTo, zTo, 0, 0, 1);
camera_set_view_mat(cam, view_mat)

//End Step Event

xTo = obj_player_placeholder.x;
yTo = obj_player_placeholder.

I am completely new to game development and I am working on my first littles games. I already spent a few hours at my favorite café and did some good brainstorming on the games‘s basic concept, the core game mechanic(s).
Now, for one of the games I implemented the most basic code for a working prototype which reflects my basic needs to evaluate if the mechanics are actually fun or not.

My question is simply, how do you in your projects decide whether to go on with the game development or whether to rework the concept?

I have some trouble to overthink too much and rework maybe too much before I actually go on with the project. When is the game fun enough to actually go on?

I need a spriter that can do Deltarune-kind-of-styled pixel art. Also, my budget is 0, sooo. Just comment if you want to help; I NEED SPRITERS 💀

I want to program a mouse (animal) whose direction is decided to be either left or right, then walks for about 1.5 seconds and that it is again decided whether he goes left or right. howéver, the mouse is only walking right, no matter how often i start the game or how long i watch it, it never goes left :(

this is the code vor the create-event:

and heres the code for the step event:

please help me!!

thank you in advance

i have been doing a chapter based game and i want to use game_change() since we are multiple people each working on one chapter. Tho, if i try game_change() it wont work. I included the data.win and the options file in the included files but it doesnt do anything. i know i have to export the game as a executable, but i tried it and its the same problem. Can anyone help?