Can someone post a list of possible blocks? I think I can come up with some interesting challenges (or not, depending on how hard the original levels are lol)
Sure. This is off the top of my head, but there are:
-wall that allows portals
-wall that does not allow portals
-the checkered field that kills the player
-the dashed field that destroys the block and removes the portals
-button (and door that it opens)
-box generator
-glass (player and boxes can't go through but portals can)
-the thing that generates the "high energy particle"
-the high energy particle receptor
