This. Is. Fun.
This is really a great game. There are a lot of things to remember, ammo type, overdrive, siege, turrets, special weapons, but the best part is that they don't get in the way of eachother. It might be a lot to remember, but they were all useful in saving your tank, if you could remember them in time.
I often used siege mode before my weapon overheated, since it would take the same amount of time to reload and it would at least do a lot of damage to hopefully hold off enemies until it had finished charging. I also liked the fact that siege mode kept you from moving, it made it easy to tell what mode I was in (So I never killed myself in the confusion) and it was also useful when implosion/shockwave/rift came up. I once press R right as a suicide nuclear tank came right in front of me, almost touching, and I used shockwave right between me and the tank, and press F as soon as it activated, throwing the tank away, and my siege mode stopping me after it threw me a bit, saving me from any damage.
There are a lot abilities here, all of them were very useful, though some very dangerous to yourself. I enjoyed it. Improving this game would be hard, all I could suggest is maybe removing the possibility of random deaths, such as when you activate implosion halfway off-screen and a nuclear tank comes flying at you.