[Released] Cassata Chamber 01
First off, I really enjoyed this map - your puzzles were very refreshing.
There are a few issues I noticed in one play-though:
- During the first puzzle, you can become permanently trapped in the tall room behind the slow-closing doors by placing both your portals inside that room.
- Some of the floor lighting does not have proper brush work - when you look in the crack you see into pure blackness.
- In the last room, GlaDOS was talking over herself - I'd assume this is two speech triggers that are too close together.
- Some of your walls do not accept portals especially well, this can be fixed though the use of portal bumpers.
Yeah the thing about putting the cube on an angle, is that it naturally does everything in its power to right itself and to get it to rest on an angle you have to drag it across the top of the door etc. Suffice to say it takes a good deal of effort and I bet most people would never think to even try and then would give up on the effort when they found how hard that solution might be especially when they prolly think its not the inteded solution to begin with. Like others have said, come up with some way (perhaps a graphic) to show it.
I think showing a door held open by a cube or some other object earlier in the map would do the job.
the first way I tried was
You don't use the door to angle the cube though, you use the angled platform beside the door, which is exactly the right angle to prop it against the door. I'll take your advice, but I just want to point out that the puzzle really doesn't require as much effort as I think you're thinking it does. 
PS: Showing a door behind held open by a box is a very good idea, I never thought of that. I'll be sure to do something like that in future maps. Thanks!
PSS: I'm aware of a couple spots in my level where you can get yourself stuck, and I'm trying to find out how to detect if both portals are within a specific zone so that I can fire a trigger to open the door. If anyone could give a link or example, I'd really appreciate it.
I believe covering the walls in that room with portal detectors and using OnStartTouchBothLinkedPortals would do the job... I'll throw together a map and see if it works.
Edit
This works fine... just make brushes 1 unit thick, give it the trigger texture cover all the walls in that small room with them. Select them all and tie them to a portal_detector... add the output
OnStartTouchBothLinkedPortals ---> Door ---> Open
since the door is slow in closing... they should be able to shoot a portal out before it closes again. And if they miss it... shooting another portal anywhere in the room will re-open it anyway.
PS: Showing a door behind held open by a box is a very good idea, I never thought of that. I'll be sure to do something like that in future maps. Thanks!
PSS: I'm aware of a couple spots in my level where you can get yourself stuck, and I'm trying to find out how to detect if both portals are within a specific zone so that I can fire a trigger to open the door. If anyone could give a link or example, I'd really appreciate it.
When I did that it would auto correct it self and go back to a 90 degree angle.
Did you release the cube and re-grab it?
You need to drop the cube on the platform, then pick it back up from an angle. It wont auto correct the angle unless it's very close to a 90 degree angle (like 80 to something).
@Rivid, thanks a lot! I'll give that a shot and then release an update for the map. Thanks. 
Overall, enjoyable map. I only really felt exploitative near the end, though, and I bet I was. ;p
Also,
I hate to use the words "Beaten Correctly" because like I say, my intention for map design is to make it seem like any way you beat it is a solution, whether or not you did it the way I initially intended or not.
So I'll use this sparingly when I say: