Feature Lava pits

In level 6 there is a zig zag of corridors above the player staring position. Once the player manages to find their way to the second level all they have to do is run across it to the other side of the screen. Not very challenging. We can modify the death field and turn it into a lava object with an animated sprite similar to the portal. From there you can place these pits so that the user must build over top of them.

So also the page on enemies. The no-edge-detection enemy could be modified so that it looks like lava and is instantiated infinitely and quickly. The result will be a waterfall type of effect where the player must build a barrier to deflect or re-route the lava in order to get past it.