I started Cookie X as a side project to learn a bit more programming in C#. Unfortunately there was little time or motivation to do much while I worked on Toy Flyer. Especially in the end phase of that project I was happy to not code on the weekend and so Cookie X sank into some kind of dormant state.
I worked a bit on collision and simple physics but the result so far is not that great. There is the problem that Cookie either flies or his jump is not even noticeable and some collisions are detected irregularly. So far I have only worked with simple sphere and box collisions but those will not work with the platform graphics that "Revenge of the Cookie" used. Implementing my own physics calculations is harder as initially expected and too much for me at the moment. If I want to finish Cookie X, I would have to use some kind of physics engine to help me out. The first project was started in Unity because of that but some disagreements let us to abandon Unity and switch to Torque2D. In hindsight it might have been better to stick with one engine and finish it there as we encountered the same problems as before.
Using a 3D engine for a 2D game might be a bit overhead but I have worked with Unity on two successful projects by now so I might switch from XNA to Unity. Another bonus in Unity is the integrated editor which frees up my time considerably because I don't have to write my own. In one of my classes at the Games Academy we will work on an editor for 2D games in Unity that will be separated from Unity. When it is finished I will integrate mine with Cookie X and could publish them together.
The progress is not lost because I can port my classes to Unity and continue from there. When finished I could even publish the game but that will only happen if I find enough time to recreate the original game and maybe finish it according to the design documents we made for the student project. When the mechanics are working and the editor is integrated I will give it to a friend who was level and game designer for the first game and he can build some levels. Maybe we will even recruit some 2D artist to create additional graphics for platforms or enemies...