Super entertaining, and I love how much it encourages strategy (regardless of the fact of being a tower defense)
In the time you were given, this game is amazing, so I would rate 5/5 even if I had nitpicks.
A few little things could be nice, such as a node when starting levels, especially with intertwined paths, showing the enemy route? You could've exlcuded that purposefully and it would make sense though
It would also be really neat to progressively unlock 1-3 more new towers, but that's just asking for more; the game supplies well enough
Overall SUPER NEAT AND FUN!!! good job to everyone involved