[SP] Banzai !!!
There are a lot of things to keep us entertained in this map. 
Nice work.
Definitely some near-ninja moves required though. I may have made it tougher on myself by using several different methods than HeadShot - I didn't get the cube anywhere near the catapult in room 2, skipped the
I think I had more fun in the bts area. 
But I'm still not sure how a
Haha, don't worry it's already empty. I think when it was full it was heavy enough to press the button, but alas, you're a bit late.
Headshot - truly amazing, it would have taken me a lifetime to sort out the solution ....impressive...
Greykarel - another amazing piece of puzzle making skill. Thanks for creating - even though I couldn't solve it...
puhh... that was a hard one... really nice
I watched Headshots demos and I solved it a little diffrent,
Sadly I have huge performance drops with gels and my solution requires very tight timings so I can't make a video.
I never used the blue gel at the upper area so it took me ages to find a solution for the last part.
I painted the start area so I can jump up and shoot a portal back to the wall with the lasergrid...
Then with tight timings and some crazy jumps I managed to drop a respawned cube on the button again while having blue gel inside the funnel.
Maybe I can record you a demo if you want.
Had much fun in this one... 5/5
Here are those different solutions I mentioned earlier:
http://youtu.be/S3nx4Vgb8mw
Wow, it's an awesome alternative way. Very clever and with exact calculation for cube and gel position in the funnel. Well done .
Now, who is gonna show me anything behind the scene?
This map was sitting in my queue for several months, silently taunting me that it still had hidden secrets.
So here is a video of the other two tasks, to complete the set.
BTS & side quest alternative solutions
I chose what I think is the cleanest way to achieve the side quest, after trying some faster routes that were less elegant and less reliable. To add some balance to the video, I broke the first room instead.
And I really wish the music would keep playing while in excursion funnels. 
YES!!! Finaly I see I spent so much time on building the BTS part not in vain. Thanks for playing it hard.
P.S. I wish I knew how to keep music playing while player is in funnel.
Wow Calmly! Awesome run! 
Totally as intended by Grey And you found the side quest, which I never did during the beta! Cheers for that!
There's still another way to get to the easter egg that I found while testing the map and that Grey kept as alternative. I recorded it:
useful tools and stuff here on TWP 
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I mentioned some stuff on Steam, but I decided not to spam the comment section, so I'll do it here. Because I watched Jose's and Calmy's videos, I managed to think of the "simple" solution. The execution is hard, so I used time slowing cheats to make the midair portals, and now that it sometimes doesn't work, I'm going to use noclip when the jump fails. I personally don't like using console commands, because it makes me feel like I'm cheating. It's probably late already, but I think there is an entity for slowing the player speed without commands and turning on cheats? Anyways, once I'm finished, I'll send a demo of what I thought the simple solution was (I didn't manage to do it yet). Good thing about maps like this is that it lasts for long, and replaying makes you find out stuff you miss or replaying just for fun which is hard to find by replaying short maps.
EDIT: The music in the map sounds good, so I looked up an instrumental version of "Waiting for the night" to use in my own map. It sounded a bit different, so I extracted the file from the BSP, and itseems like you edited it?