Make sure you select the kongregate export option,

if there are any further problems be sure to report bugs at github.com/Scirra/Construct-3-bugs

The issue is that a sprite is bleeding into it.

To fix it, find your sprite in the spritesheet

Then once you found your sprite with the lines in it, look for the surrounding sprites, one of the nearby sprites will be of the same color as the line

Find that adjacent sprite in your project and use the crop transparent edges button

this will put transparent edges on the sprite that is bleeding into other sprites so that the bleed will be transparent pixels and therefore it won't be visible.

The actual issue is that you'Re using linear sampling and so it samples pixels from adjacent sprites sometimes if they don'T have transparent pixels because that'S what linear sampling does it mixes color values linearly. My solution will fix your problem

upload it on itch.io or knogregate

The problem with all of those third party solutions is that they don't allow you to write the server-side code with construct 3

Also most use websockets which is slower than the webRTC implementation construct 3 uses (construct 3 uses websockets to establish it's webRTC Connections but webRTC does all the work)

I find it baffling you people suggest worse 3rd party solutions over our wonderful built-in officially supported multiplayer, enlighten me on this if you may

But now with Construct 3, people mostly gave up on the multiplayer plugin and went for the alternatives like customized plugin, customized back-end, WebSocket System or 3rd party plugins like Colyseus or Photon Cloud / Server.

People didn't give up on anything, you just told people to give up on it and and the people trust you