If it doesn't affect all txthighscores you have either already picked only a part of them before going into this event or you try to reference txtobjects you've just created in another subevent of the same event (it is a bug).

Well if it is the same object:

for each TxtHighscore: set text to array.at(txthighscore.iid)

Why not just use 2 conditions instead?

a.x = b.x

b.x = c.x

or if it is the same object, something like:

pick the one sprite you wanna check, set a local variable to the x of the sprite

after that

pick all

pick by comparison, x = localvariable

if sprite.pickedcount = 3: do stuff

The browser object can execute external .js: scirra.com/manual/110/browser

for security reasons it is safer to code a plugin with the SDK instead

scirra.com/manual/15/sdk

you should ask your questions about sdk development in the sdk development subforum, though maybe your question is already answered there

Pin behavior or

add player.x to your equation

If your image point is in the middle of the sprite and the sprite is 20x20 pixels big, imagepointx(1) will give back 10, no matter where the sprite is.

What do people learn in maths these days? Calculating differences is taught in elementary school.

But at what performance, that's the question. Not if it is codeable - we know it is.

It all depends on the level of detail and style you want to deliver imo. Make it as big as it needs to be. Take playing on larger displays into consideration when thinking about how you handle those - will you scale the game up; if so, will you only scale by the factor 2 so that the pixel style won't be blurred that much or do you always want to fill the whole screen. Or do you want to keep the original size always, 1 pixel of your sprite always showing as 1 pixel on every screen (probably not very usable except when you are coding for desktops).

I think performance would drop in endgame when I look at a video of the game in later stages. I can't make a good estimate though, maybe I am wrong.

The right side of your image (in image editor) will be the front.

Check for collides with multiple sprites: use a family for that OR an OR-block if you are using the free version of construct 2

no idea why it would work with rotation and wouldnt work without rotation

You can't modify families ingame.

Simplest option would be putting all sprite objects into one sprite (each sprite having its own frame - or if it is animated: animations) and add something like this:

scirra.com/forum/random-frame-uniqe_topic80520.html

If that is not possible (because of the sprites having different behaviors that would collide with each other), you probably need many subevents, 1 for each object to be created.

Is fullscreen scaling set to off? It is possible that it is blurred because of the zooming in.