One more piece of advice: START SMALL.

A lot of people have this first game idea that is this huge platformer quest or RPG or something that will take years to complete. My advice would be to pick a small project that you know you can finish in a few weeks or months. Project 2 can be bigger, but while you're learning, it's so important not to bite off more than you can chew.

Perhaps try changing the object scale, not size? If I recall that should preserve mirror state just fine.

Well, how have you coded the slide? Are you able to add a collision test so that the slide always continues until clear of the wall / else slide lasts for the normal duration of the slide?

I'm speaking vaguely because without more information about how you've gone about this effect it's hard to say specifically what to do. Can you post some of your events?

Can you post an example image of how you'd like the effect to look?

Anything's possible, but this might not be easy!

This question doesn't really make sense. What are you trying to do, exactly? Why would you need an instance variable to be an expression?

I was able to see your image, but I'm not sure exactly what you're asking. What are you trying to do?

Aha! Progress!!

Turns out I had two problems going on that were independently causing graphics bugs. I'd already tried setting the scale to an integer of 2 but had noticed there was still some weirdness in my tiled backgrounds so assumed that that wasn't the solution. Turns out that it was the way to go, and that I'd stupidly also made some of my tiled backgrounds at weird sizes, so they weren't tiling properly! Some of these graphics I made years ago when I was learning C2 and I guess I made them wrong - that brick texture was like 31x35 or something?? Wtf was I thinking? I remade it to be 32x32 and guess what, it displays properly now -_-

Thank you for your help! I guess I'm going to have to adapt my game to the 2-scale now - it shouldn't be too drastic of a change, just a few levels need to be reworked but that's ok

EDIT: Oh, and switching to Integer Scale mode was essential.

It is the horizontal lines that are disappearing. I had that happen in a game and if I remember correctly I fixed it by having the editor image at original size and then setting the image to the size I want in the settings and you may have to play with those settings to maintain the proper ratio.

This sounds promising, could you elaborate? I'm not completely following you. The settings for the sprite object? Everything is currently in the layout editor at 1:1 scale, with the entire layout enlarged by 1.8 scale in events. What do I change, without rebuilding my entire game?

Also recheck your image points have not slipped out of line and if there is any white or light gray borders around images crop them off as that throws off the alignment for some reason and run it in letterbox integer scale.

My image points are okay and this occurs with tiled background objects too (ie the bricks in my example image) where the image point defaults to the top-left.

Oh and check your layout and view scale. They need to be in even increments of 16 pixels like 640x640 otherwise the raster will miss pixels and that would explain why the horizontal lines are missing.

My game's native resolution is 1280x720 so that shouldn't cause any problems, although it looks weird both in window and fullscreen. How would one set the view scale to something divisible by 16?

Thank you for your detailed reply, it's encouraging to know somebody has fixed this problem, although I haven't found the fix I need yet

Again, the problem still occurs whilst using no effects. :/

There is a tint layer with Overlay fx, otherwise no fx (and the problem occurs without it). I have tried every fullscreen scaling setting

Right, I tried setting the layout scale back to 1, and things have improved, but some pixels are still displaying all fruity. Look:

The differences are subtle, but the bricks in the background are missing lines, and part of the windowsill has disappeared.

All images are cropped.

It's all sprites, all 1:1 size. Although, actually, come to think of it, my layout scale is set to like 1.8 or something in the events if I remember. Would that be the culprit? I like the size that things display in the output, is there a workaround that would allow me to retain that scale but display pixels properly?