Version 1.2 is here! It includes:
the background object replaced with a single transparent pixel, since it is redundant with the new background support. This way, it won't affect any previously made levels.
4 new pieces of terrain in all 10 colors! These include an arch, a small arch, an "eye" piece, and a rounded ledge piece which give you more options for structures.
The steel now differentiates itself from the Metal tileset pieces by including the screws in the corners and sides.
2 new traps! One for the walls, and one for the floor/ceiling! They are technically the same trap, but they use two different objects due to the rotation messing up the trigger area.
Enjoy, and if you have suggestions for future pieces/objects, please post them here! I would love to hear some input! I have planned on putting in teleporters/receivers for the next update as well.
EDIT: Put the attachment on the first post to make it more convenient for people.