Due to some severe issues with RPG Maker and now Unity, I will be restarting development of Collision in the Godot Engine. As a result, Collision will be removed from steam on October 20th. I do plan to repost the steam page when the time is right, and all current owners of Collision will have access to the Godot Engine version when it launches. I am sorry for the slow progress, as I have entered a state of development hell.
Thank you for your patience.