It is still fun, glad to see some lore slipping into the game now. I played the tutorial and the first few missions, got the big-ass gun etc. I am very curious to see where this goes storywise. When it comes to immediate upgrades I think making some real environments would do a lot for the game feel.
Controls work swimmingly.
Can't wait for an actual mission with story and characters with this sort of gameplay.
If I have any other input I think it would be to not be afraid of making the main tank unrealistic, upping the speed, the speed of the realignment of the barrel and so on. It does not seem like this will go for simulation, so tweaking things towards "fun" may be good.