Make clear that it is allowed to build on creep paths

[Supersonic112]

Quite a few of the people who tried the game at the past vernissage believed that it was forbidden to build towers on the path of the creeps. (They didn't even play or see the tutorial in which it IS impossible to build on the main creep line)
To solve this, we could make the creep paths transparent or show in real time what path the creeps would take if the player placed a tower where the mouse is at that moment.

[nczempin]

we could also place a transparent tower instead of the current cursor.

[Supersonic112]

Good idea, we could go for the "red=you can't place it here, green=you can" system that is used by many strategy games.

[nczempin]

that's probably worth several issues:

1. previewing the paths
2. using transparent towers
3. red vs. green