People got stuck in the shortcut doors - now fizzler+laserfield.
Removed annoying fizzler in the first room, idk why it was there, hopefully nothing important.
Added reset room for room#4.
Improved the stairs bug - the level is actually finishable now, though stairs still have broken collisions.
Moved the signage for buttons a bit.

Added a fizzler for a wall and a target on the floor(to catch attantion and hopefully make them look up)in room#2.
Changed bts logic in room#4. It resets faster and more consistently now. Ball-room fizzler now resets too, door closes when the ball is removed, to add more puzzle into the room.
If you lost most/all of the cubes in room#4, the level would be softlocked before. Now you can use main room buttons for the cubes(if you have already been to room#4) to reset the security. The problem is, that it requires you to collect the cubes again. Unless someone doesn't have an ability to restart and have to stay in this chamber until they solve it, most likely, noone will ever even try it. But it wasn't that hard to do, so let's hope some hardcore roleplayers come one day, or maybe all of this will actually be happening in the future.

v1.1 Reworked room #2 to enforce the intended mechanic. Removed supereasy unintended solution from room#4. Design tweaks for room #3.