Nice Game, it makes really fun to play!
Played it with Schokokeks to Wave 7.. Then died ^^

Things which can be made better or should be created:

-Ingame Menu , to in/decrease the Mouse Sensivity
-Afer Setting the whole Defence, a Button should be appear, which you can start the game without waiting for the Counter!(All Players must accept!)
-Delete Crate Function, if the user created a Crate at "the false" position
-Enemy's left Digit
-Player's Score Panel(which can be opened wiht TAB or something else)... This Panel shows the Current Users / the Score / Ping and Kills from all Players.

cYa Sebastian

Tutorials:
[Blender]Terrain creation ENG/GER
[Blender]Low Poly Tree Modeling
[GIMP]Create a Texture for Terrains
CLICK HERE