I liked the gameplay here. It preyed all my addiction to constantly level up my stats like other tower defense games and the process of gaining new turrets by jumping to other tracks was innovative since it gave the player something else to do instead of just watch. If you ever plan on working on this game again, I would suggest refining the inventory and management system like maybe just reordering the animals or switching them out. I learned that strategy games, which I feel like this game is aiming for, are often good when they provide free management of assets.

Combining mobile autorunner and tower defense gameplay styles with Noah's ark and trains is such a cool and very unique idea! Great job! :)

(If you continue developing this idea, you could give each animal different attack types. Plus, if you combine two of the same animal on one train car, they could get boosted stats, thus serving as a reference to God's command to fill the ark with two of each animal. You don't have to use these ideas of course, but I just wanted to share some thoughts I had...)