The lines are created with sprite trails parented to a func_rotating which is parented to a func_movelinear.
I used a movelinear because you dynamically control how far it moves. The starting position is underground (0) and then it moves up to position 1. At position 1, it STARTS moving back to 0, but return to 1 after a second or so.. rinse and repeat. Source is nice because the movelinear triggers itself once its fully open - once set into motion, it's automatic and forever.
As for the other stuff, its just a sprite, some sounds, 2 fades, an actual teleport, and a spark effect when you land.
I'll outline everything in the example map with the prefab. I just don't want to release it yet because im using teleports in my compo map.
If you want a goldsource analog, its totally possible...
The circles can be replaced with ring beams riding path tracks. The advatage of beams is their ability to toggle on and off. The spritetrails i used in source are always on - which is why the mover-parent spawns underground.
The teleport doesn't work unless its active, and masters can be used for that.
Sprites are simple in goldsource. start off, toggle on when tele is active.
Everything else is just sounds and timing.
Ambient generics and multisources will work fine.
Goldsource has env_fades too so everything should work with some effort.
The only disadvantage is that mysetup uses around 15 entities so renaming and relinking them will be very tedious if you want more than one.
So i used the "&i" extension on all my entities when i made the prefab.
If you paste a prefab in the map, teleport01 will link to destination01. paste another, everything gets renamed to 02, and all the links remain within themselves... So nice