I'm interested in creating a 2.5D first-person shooter (like Doom) and I currently don't understand how to implement the player moving forward. The player will also be able to browse around the world (left, right, up, down) via gyroscope control. I plan to only use 2D sprites and no 3D models.

My first attempt was to increase the scale of layers to make it appear as if the player was moving toward the objects but I'm not sure how to make it seem as if the player is passing around the objects (instead of running into them).

If there are extensions that I should take a look at (like Cocos3D), please let me know. Thanks for the help!

Note: I've only created 2D games so was hoping to get guided into the right direction