I liked your game - it's very good, especially considering that you did it in a couple of days. This and the flight-game screen shot show that you're quite quick and talented at doing these things! And also resourceful - I mean to pull together the 3d graphics and physics and textures and all that must be pretty hard. Does JMonkeyEngine do that stuff pretty easily?
In fact I can't say very easy, I struggled with textures too much. May be it is because I am new at jmonkey. Anyway there are very useful things in it, I recommend it strongly.
I deal with physics by myself. Such things doesn't seem difficult to me, may be it is my plus.
One other small thing - the starting menus are pretty bad and look terrible - it seems like they only choose a fast tank or fat tank, so why not just have one in-game menu for that and not use those ugly Swing metal look and feel menus?
As I said I am new to jme , and I didn't want to waste time with learning and applying such things to these two games. In flight game my aim was to achieve some specific things in my mind only and with this tank game I only wanted to make a good code design, nothing more. I didn't think these games as something that people would want to play.
This and the flight-game screen shot ..
I also put the flight game itself, check it out