invaders | Space Invaders in Go | Game Engine library

I´m building my own Space Invaders in Java with Greenfoot and I have a Spaceship which shoots the Aliens, but the Bullets stop at the top of the map and stay there so I wrote this method which should remove a bullet if it hits the top of the but it doesn't work. What´s the problem?

I am coding a space invaders game in pygame, and wanted to make it so that when the player reaches 50 points, the game increases the number of invaders from 6 to 10. In the game, the enemies respawn near the top half of the screen immediately after dying. The game functions perfectly normally until you reach 50 points, at which it immediately crashes. How do I make it so that the variable storing the number of enemies (num_of_enemies) increases, while the game is still running?

In the code I have put here, I removed my attempt to change the num_of_enemies variable, but fyi, I placed it just above "pygame.display.update()". my crappy attempt to resolve the issue boiled down to:

if score_value >= 50: num_of_enemies += 10

I have also tried this code while assigning num_of_enemies a global value, but it simply defects the game, and messes up again.

Code:

Attempting to make a space invaders style game, and I want to affect all enemies using a for loop - but with the code shown I get a logical error where only the 1st enemy is affected, and only the first enemy can access/use the enemy.moveLR() method within the enemy class. The method of the class is not highlighted as yellow, nor does VS Code's intellisense pick it up.

Code concerning the enemy:

so I try to program a 2d game platform like space invaders, but the problem is in the collision, when I try to define the collision, which I use in her characteristics, the characteristics of the classes (enemy coordinates and the bullet coordinates), the code won't start. And this is the result : `

I know lots of people have had issues with flickering images in pygame on here, but none of the responses have helped me. I am trying to make Space Invaders, however, the bullet flickers as it moves up the screen. Please try to help me, and thank you! I do not currently care about the size, position, or scale of the bullet, I know it does not look great, but I just want it to display properly! Below is the code:

Good morning everyone: I'm currently doing a version of space invaders in a world without limits. I have already done everything, but I have a problem with the laser beam. When it doesn't hit the alien it doesn't destroy when it reaches the upper limit of the world, it comes from the bottom since the world doesn't have limits. I want the laser beam (turtle) to die when it reaches the max-pycor but I don't know how to do it. If you can help me I will appreciate it.

Here is an example of what I want to do

I have to create Space Invaders for my programming course in college which would be fine, but I have a problem with removing a bullet from the game after going off-screen. In the game, the bullets move to the right and should disappear after leaving the screen, but I do not know how to create it.

It's a module of bullet structure

GOAL
So I have a space-invaders type game I have made to practise unity and I want to upload it to Itch.io as I have done in the past. This is a clip of the game.
I switched platforms to WebGL in Build Settings etc, and everything worked fine in Unity.

PROBLEM
However when I built it and uploaded the zip file to Itch.io, the aliens are now a lot faster than usual.
(Be aware there may be other things that have changed, I just haven't been able to get to them since it is extremely hard).

CODE

Alien movement:

So I have made a game using Pygame, and now I want to make a executable out of it(standalone executable is preferred). So I used this to make the executable: