Well - I guess you knew this one was coming :) - Can you add towers to the level editor that you cannot sell in game.

You could just tick the "Sell Towers" box in the level editor?
This disables/enables selling of towers.

I think he means, the level maker would be able to place towers the player can't sell, but will need to use during the level.

^^ exactly

I guess anything is possible. This feature would require a bit more work that the average feature. I could think about adding it after I get some other features compelted if that's what people want.

sound fun :)

I like it! It opens up a whole different style of map: The style where you've already built a maze on screen that they can't change (because they can't sell any of the towers), so all they can do is upgrade those towers and hope for the best.

You can separate the two things there, though. Whether or not you can sell the towers that you put up in the editor should be an option, in addition to (not instead of or added to) the option of whether or not the player can sell their own towers.

I support this thread!