For Windows Phone Apps, when you deploy the app to your phone, it either will be deployed as App or as Game. If it was deployed as App, then you can find the App in the App list. And if it was deployed as Game, then you have to go to Game App in the App list, then you can open your app there.
How to change:
Change to Game:
In Properties folder, open WMAppManifest.xml using XML NOTEPAD, then in the App node, update the Genre attribute from "apps.normal" to "apps.Games".