I really liked 3D environment, and I believe there is beauty in the simplicity of the game idea.
I think it would be nice for the gun to shoot directly at the point the player is clicking on, even though it's being shot from the hip.
It was frustrating to have to keep clicking on a non default ammunition type each time I wanted to use it. I also managed to crash the game by running out of bullets.
Overall I think it has a lot of potential to be a fun arcade game, and I can understand how the 'learning' theme is supposed to fit into it.