For me, although the timer was tight, the big problem was the poor sight line to the flip panel. If that was better positioned, I wouldn't have wasted precious fractions of a second aiming at it. Move that one section to the right, and another second to the timer, or both.
Also, think of an escape hatch for when you get stuck out there.
The frustration factor really killed the fun of solving an otherwise decent puzzle.

Horribly designed map. I see what you wanted to do, there are some good puzzle elements. These are ruined by the other skillz elements. Moving a cube onto a weighted button is ridiculous. The time limit is also quite ridiculous. Thumbs down, no rating because I refuse to finish it.

Just 'noclip'd my way around the rediculous time constraint. Screw it

For me it's spoilt by the short time limit.Once I've worked out what I need to do I like to harvest those fruits but there is not enough time for me here to do it. I'm not a seasoned player but, for me, short time constrictions are NOT in the spirit of Portal 1 OR 2

hmm.. well you're supposed to bring the cube up to the lightbridge and the fizzler there should be a way to prevent that. but you need to be able to put a portal there. i think i get how you did it and that indeed is not the intended solution. i think i have to rethink the whole thing. thx for the feedback

Everything after getting the cube onto the button at the far ledge is trivial and adds nothing to the puzzle IMO. You might as well just end the puzzle there (This is very much IMO, though. See what other testers think). This would take away a lot of the apparent complexity (= number of testing elements and connections) while keeping the actual puzzle intact.

Lighting and visuals are fine. Indicator lights are a bit messy, especially near the button which turns off the fizzler between the main chamber and the entrance/exit - these are actually hard to read. Consider using lights to force the indicator lights to go in a different direction. The indicator lights for fizzlers (and laserfields) go to where the actual fizzler object is placed (the one-tile segment where you originally placed the fizzler); by moving this around you can make the lights neater.

Try to reduce situations where the player gets stuck and has to kill himself or reload a save.

Drop the cube on the elevator button from off the light bridge, then move back across the portal. (Sometimes the cube doesn't want to land on the button nicely. It's possible to drop down, put the cube down normally, stand on the cube, then jump and move the light bridge underneath you at the top of your jump, which allows you to get back.)
Move the portal at the light bridge side off to the left a bit (but not so much that the bridge doesn't extend through). Put the other end near the elevator. This puts the light bridge close enough to the elevator that you can just jump across.
The rest is probably as you intended.

(this limit is so annoying)

F4F response. It's a reasonably good map.

It's possible to snipe a portal behind the fizzler at the end of the light bridge which shows up when the funnel button is pressed. Is this intentional?

I'm think my solution might be unintended. Here's how I did it:

Use the funnel to get the cube in the way which is probably intended. (I never use the funnel again.)
Portal-snipe the end of the light bridge, then shoot the other portal at the ground level surface. Walk across the bridge through the portal, then move the bridge near to the elevator button.

(continued in next post due to 1k char limit)

thx, I increased the countdownfor 1 sec. should be ok now.

Fun one! At first it's quite overwhelming, but when you figure it out, you'll think why you haven't thought of it earlier. I had some trouble with the timer though, got "stuck" in the panel a couple of times, but it certainly is possible.