[Coop] Tests of cleverness
I'm pleased. Your map is nearly perfect and allowed no unintended solutions. ^^
Chamber 4 there are a litte glitch with the left button. I can jump on the button and wait for the other player (watch minute 31:40).
My English isn't so perfect, that i can talk the whole time in English! 
...therefore there are much english player, but a few german... :/
But you're right, I tried this map before with another friend ...rofl, we solved only the (little) first and second chamber! xD ...so it was like a blindrun. 
I will do it!
I rated it with 5 of 5. Difficulty is medium ...great ideas and puzzles and good design.
Wow. Threadnomancy engaged - I made an account on this board just for that purpose! 
This map, as your others, rocked. Simply Genius.
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However, we did have one unintended solution, I believe.
In the test-chamber with the angled laser going onto the angled plate, where you need to place a portal in order to route the laser through the angled portal into the laser-receiver.
One player goes through the fizzlefield and stands on the button in order to disable the fizzlefield. The other places a portal in the ground beneath the red-death-rays, and one outside where the first player can then drop the cube into.
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On our first two playthroughs, it did not occur to us, that the intended solution is:
> Player outside drops the cube in the portal
> cube goes through, bounces against the ceiling
> cube then swings up and down through the portals like a pendulum
> the player who dropped the cube simply walks through and picks it up.
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What we did was:
> start a countdown
> wait for second 2 to show up.
> drop the cube immediately
[[ Player inside stands on the very edge of the button ]]
> Player inside then trys to get off the button and catch the cube, before it comes down again.
[[ many many tries later ]]
> figure out that the player on the button needs to run forward just before "1" is over and "go" appears
> catch the cube.
Then yesterday I showed the map to a friend, and he figured out the intended solution.
I felt retarded
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On the plus side, our way of figuring out a really really tight timing was really alot of fun and we felt like we really accomplished something once we achieved it!
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Now, I have played all your other coop maps - all splendid and wonderfull.
Sadly, on my search for other such [coop!]-maps with similar degrees of difficulty, i was out of luck. 
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Anyways, best wishes
archont
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PS: Excuse the bad language, English is not my mothers tongue