So the file format is pretty simple. I just documented all the ID#s for the items that are available in the level editor, and how the file format is designed:
Two ways to see it. A
Line 1 is the number '1', and a reasonable guess would be that it is a version number for the file format.
Starting at line 2:
Items are saved in the save file in the order in which they are added to the world. Any new ones added are always at the end of the list of items, even if some have been deleted earlier. Lines 2-31 are 10 things which exist by default in new custom levels. 8 of them are 'Ground' tiles (which are tiled across the width of the map). The other two are 606 (Conway) and 215 (the exit). The city backdrop and fence and such do not appear to be in the level file at all.
Items are written as sets of 3 lines:
Item ID#
Doesn't seem to be in any particular order
X coordinate
Lower numbers are closer to the left side of the screen.
0 is when the left side of the object is at the left side of the screen.
X is a negative number if the left side of the object is off the left side of the screen.
Y coordinate
Lower numbers are closer to the top of the screen
0 is when the top of the object is at the top of the screen.
Negative numbers for when the top of the object is above the top of the screen.
Coordinate units are 8 per tile for both x and y.
Standard Item IDs:
Walls and floors
Ground, 489
Wall, 70
Normal Floor, 136
Wide Floor, 257
Narrow Floor, 282
Doors
Door Frame, 214
Closed Door, 53
Open Door, 55
Hand Scanner, 54
Windows
Right-facing window, 119
Left-facing window, 123
Right-facing window frame, 120
Left-facing window frame, 124
Glass ceiling, 211
Glass ceiling frame, 281
Stairs/Elevators
Stairs, 610
Elevator doors, 608
Elevator, 32
Zones
Indoors, 615
Dark indoors, 616
Wide indoors, 617
Wide dark indoors, 618
Electronics
Light Switch, 56
Light, 69
(Dark) Light, 374
Right camera, 114
Left camera, 150
Alarm, 116
Motion detector, 294
Security door, 132, (the ones that stay open only temporarily)
Power socket, 131
Trapdoor, 412
Circuits
Green box, 110
Yellow box, 111
Magenta box, 283
Blue box, 107
Green dot, 113
Yellow dot, 112
Magenta dot, 284
Blue dot, 104
Guards
Guard right, 6
Guard left, 76
Enforcer right, 169
Enforcer left, 290
Professional right, 166
Professional left, 167
Patrol, 356
Objectives
Main objective, 72
Laptop, 173, Secondary objective
Exit, 215
Conway, 606
Back walls (None of these have names in the editor)
White tiled, 216
White tiled wide, 620
White w pillar, 252
White w window, 243
Blue brick, 363
Blue brick w window, 372
Brown brick, 490
Black w brown brick edges, 495
Brown brick w window, 497
Grey double-width, 493
Decor (None of these have names in the editor)
Filing cabinet, 272
Barrel, 230
Brown Desk with chair, 233
DATASEC desk w monitor, 234
Shelf occupied, 269
Potted Plant, 270
Potted Tree, 250
Server cabinet, 238
Vent/Box Fan, 241
Couch, 248
Vent/duct, 277
Roof vent box thing, 260
Solar panel, 261
Equipment
Battery, 513
Start with crosslink, 612
Start with wirejack, 613
Start with resolver, 614
Experimenting with other item ids now.
1 is an actual player, which is amusing in that you can run around while in the level editor itself, until you crash Gunpoint by colliding with something which wasn't meant to be collided with by a player who isn't supposed to exist in the level editor. :V