AFAIK what's happening is I messed up the equations somehow and it's writing to the wrong spot in RAM.  This explains the corrupted y-vars that are created every time I created a level.
What I had tried to do was come up with formulas to draw a border around the level, since I can't rely on the screen boundaries to limit the level anymore.
:...
:i and j are the top left corner of the map
:h is height
:m is width
:p in the appvar pointer
:vars count from zero
:...
:GetCalc(Str1,H+1*(M+1))→P
:For(A,0,H
:
:.1 is a solid block
:1→{P+A}
:1→{H+1*M+P+A}
:End
:For(A,0,M
:1→{M+1*A+P}
:1→{M+1*A+P+M}
:End
:
:.pre-define start and finish to avoid crashes--how ironic :P
:3→{M+1*P+1}
:4→{M+1*P+2
:End
:While getKey(54):Pause 10:End
:End

It's working better, at least not flooding the RAM.
If this equation-refusing-to-work stuff keeps going on I'm just going to drop the border junk altogether until i have everything else done.  Call the ability to run through the RAM at random an easter egg
:H*M→R
:GetCalc(Str1,R+2)→P
:H→{P}
:M→{P+1}
:P+2→P
:0→{P}
:Fill(P,R
:
:For(A,0,M-1
:
:.TOP
:1→{P+A}
:
:.BOTTOM
:1→{M-1*H+1+P+A}
:
:End
:For(A,0,H-1
:
:.LEFT
:1→{A*M+P}
:
:.RIGHT
:1→{A*M+P+M-1}
:
:End
IIRC, H (H is for Height) and M (think of an upside-down W for Width, I guess) count from 1 now.
Btw if you're curious why on earth I'm using H and M of all the vars, I was running out of letters to use and they happen to be close to another.  Better than something like D and G, anyway.

Thanks
What I'm focusing on is making the editor display the level right.
And ensuring it edits the level instead of the VAT.

What's strange is the scrolling from every direction displays different things.  I'd scroll a few lines off screen and when I scroll them back on it's different.
Even the initial display is wrong...and the editing doesn't work with any way it displays

Progress is being made, though.  There's just a ton of it to be made.
What I might do is make it so the user could select a section of it and that part of the level shows instead of bothering with scrolling around.  IDK at this point...

Indeed.  I'll need to look at some other source to get ideas of how to do this properly, because whatever I try doesn't work

how about moving tiles? (or actually, moving objects you can stand on , not necessarily tiles)

Yeah, I had the same problem too, since none of my games use pixel detection.
I was thinking make a delay between when each one disappears and the next one appears to give moving room, and slow it down a bit.

Are you using tile-based teleporters?

Fixed the portals, they now work seamlessly.
Added one-way tiles completely, currently debugging wall switches.
Idk how to describe them, I guess the closest comparison are the tiles which looks like + signs in cubes, but not really the same

Now I just need to come up with some sort of 4*4 sprite meaning "invisible wall"

EDIT: just noticed, the # of tiles is kind of staying the same as the date...there's 17 tile types now (not counting zero) and it's the 17th as of now here.  So I guess by the end of the month I'm really going to need a more intuitive tile-selecting GUI with ~30 tile types

Keep the tile ideas coming , it's getting simpler to add them

EDIT2:
Switches are working now, user can choose whether they default to on or off.
Also, the prog ran over the 8811 limit last night, so as of now the game and level editor have been split apart into separate programs.
Next: tiles that disappear a bit after you walk on top of them.  If I get that done fast enough, than door/key after that.