Ps: I am sorry if it is a completely dumb question but what is the value of bullet speed in construct 2/3? I am asking out of curiousity. Is it pixel divided by time in miliseconds?

The 'Speed' property of the Bullet behavior describes the bullet's initial speed, in pixels per second.

There is no 'baseline' and no right and wrong. You have to decide for yourself how easy or difficult your game should be. What do you want to create for a gaming experience? Maybe you also let the player choose the level of difficulty. Create global variables for the Bullet Speed and your 'Every X seconds' conditions. The higher the difficulty level, the more enemies spawn and they shoot faster. You will not get around testing some values until you get a satisfactory result.

If the Enemies have different weapons with different bullet speed, your global variable "EnemyBulletSpeed" could be for example 1 for medium difficulty, 0.75 for easy and 1.25 for hard. Then set the speed of the bullet on creation to > object.bullet.speed * EnemyBulletSpeed <

The 'set layer color' action was just an example to demonstrate that the buttons work. Dont know if you want to keep it.

What do you mean by 'nothing'. The project does not even start or the buttons do not work? I opened your file and the buttons worked the way they should. Start your project in debug mode and check all objects.

It is not that complicated if you change platform values at the right time. Try this example:

1drv.ms/u/s!Ap_-qxoGKbDcg2m_rsA7NkfcrcJa

If I'm not wrong then that's how it is: Magnitude is the distance in pixels from the center to the amplitude. The magnitude is covered 4 times in one period. At magnitude 50 e.g. Start center to amplitude right = 50, from right to left = 100, from left to center = 50. This adds up to 200 pixels in x (= Period) seconds. So "4 * Magnitude / Period" should give you the pixels per second.

Correct me if I've twisted something.

I would not use 'Trigger once' for this. There are rather few cases where this condition makes sense.

Better compare the opacity to prevent the action from running every tick. Also use a 'For each' loop because it could happen that with fast cursor movement and close together buttons, several buttons are activated. I also recommend to use animations instead of Scale for activated buttons. It is easier to control and prevents the button from jumping back and forth when the cursor is over the button with Scale=1 but not with Scale=0.5. Here an example:

1drv.ms/u/s!Ap_-qxoGKbDcg2iYFUp8b_Qce3yn

And what exactly happens? Because in my example it works fine:

1drv.ms/u/s!Ap_-qxoGKbDcg2d6Nk732mQwvDXy

You used 'set position' instead of 'set position to another object'. This should solve the problem. After player death the coordinates return to 0,0. If you want to keep it like this, you need to add another condition beside 'every tick', for example 'Player is on-screen'.

'Period' is the time the objects needs to complete a full movement back and forth. So you could call it "Speed".

Try another system condition 'Pick by comparison'. This should work: