Alright, I won't beat around the bush on this one. This game is a bit rough, and I'm sure you already know that. But: the fact you made anything at all means you've gotten way farther than most people. Take what you've learned from this experience and keep going! You'll be making great games before you know it.
A couple pieces of more specific advice:
The visual glitch where it looks like your sprite is teleporting when you turn around is usually due to the sprite being centered incorrectly. I haven't used game maker but if it's similar to an old engine I used to use you need to tell the engine where the center of the sprite is, or it will use the corner of the sprite as the center causing that weird offset to occur
In your instructions, you tell me to use the arrow keys, the space bar, and the left mouse button. I don't have 3 hands, and I can't push the space bar and the arrow keys with one hand at the same time. That's why WASD keys are the preferred directional buttons for most games. Make sure all the buttons used for your game are accessible at all times by 2 hands without much effort. This includes menus. If your game only uses the keyboard for input, don't make me use the mouse to click buttons on the pause menu, because it makes me move my hands (you didn't do that in this game, just as an example)
Keep trying and improving! You've got this