If you create Object_A with coordinates 100, 100 on a layer with parallax 0, 0 the object will stay at 100, 100. If you move Object_B towards Object_A and B is at 5000, 5000, it will still move towards 100, 100 although Object_A is visible on the screen.

To calculate the Parallax 100, 100 coordinates you must add the viewport to the coordinates of Object_A. But when the camera is moving you change the viewport too and Object_A will move away from Object_B until they reach the edge of the layout (provided 'Unbounded scrolling' is disabled).

I dont know what exactly you want to achieve or how your game works, but I have the feeling that you have to rethink something.

All sub-events under 'every 5 seconds' run only once every 5 seconds, so your 'every 0.5 seconds' event can run only every 5 seconds for once. You have to seperate those events. Give your houses a boolean variable and set it to true when an instance is picked:

Can you say what exactly you do not understand or is everything unclear?

Click on the layout in the project bar on the right and change the size of the layout in the property bar on the left, if that is what you mean with grid/work space.

What art style do you use in your game? Try some of your project properties to achieve better results when scaling. For example, if you are using pixel art you should switch the 'Sampling' property to 'Point':

For the requirements, if you have optimized your game based on Ashleys blog posts and tutorials, It is very unlikely that a PC can not handle your game unless it's from the last century.

if I understand correctly tinypng converts png-32/-24 files into png-8 files. The tutorial says:

Don't import lossy image files (e.g. PNG-8 or JPEG) in to Construct. They are always stored as lossless PNG-32 until you export, at which point it respects what you've set in the Image Format dialog.

C3 already tries to achieve the best results with lossles compression:

Next, all PNG images are run through a tool called PNGCrush, which tries lots of different ways to compress the image and picks whichever results in the smallest file size. This often gets an automatic and lossless 10-15% saving on the download size, but can take a long time. If you turn off the image recompression option on export, the PNGCrush step is skipped.

Its because you reset the sticks position on any touch end and not when the touch ends which controls the stick. Change it like this:

You can let the enemy who saw you spawn a alarmzone and every enemy which overlaps it, comes in fight too. In my example i destroy the alarmzone with fade out: