So, the level wich I'll soon post uses voxatron editor as it is possible, and I can't use the editor at it's maximum potential witouth noticing some bugs, and I'll list them down here:

Item placement
The item placement needed for the level is not quite the exact thing, the real object in the game (with an static animation) is acutally a few inches appart from the position it should be.

Snow covering the void
I believe this one explains itself.

Not working portals
It seems like the wrong placement actually also happen with some two-way-portals making it impossible to go from one room to another.

that's all for now, hope this will be fixed soon but I would like a way to contournate that before 0.2.6
the ways I found:

Making two way portals with normal portals, using the character position works, since the normal portals doesn't have that bug.

don't place snow on void levels.

Thanks, I've bug-listed these. Item placement & snow+void will be fixed in 0.2.6.

If you have time, could you send me an example of the portals placed so that it's impossible to go to the next room? (hey at lexaloffle dot com) I've messed with the collision code since 0.2.5, so need to be very careful about breaking doors (the most annoying bug!).