Very good start
Here are way I'd look to improve it.
1. Add another component to the bots. This compoent would be called AI chip. Here is what you could pick for AI chips, Aggressive, defensive and patrol. Aggressive would lock onto a bot and continiously attack that bot until it dies. The drawback is given it goes against a bot with a long range weapon that is defensive. The next one is defensive.. bot will only attack when in a big group and constantly runs away. The drawback to this bot is it leaves the other bots who are also running away prone to being outnumbered. The next bot is patrol this bot just runs around aimlessly attacking whatever bot it sees in front of it but not focusing on 1 single bot. This bot has no drawbacks but nor does it have any real direction. Also have it have levels or aggresisve, defensive and patrol, Level 1 though 5. Each level would become smarter in what it was suppose to do
2. Each upgrade level on the guns you should be able to pick between Range/Weak, Mid-range/average and short-ranged/powerful. This choose of weapons + AI chip would allow people to customize their bot actions without acturally moving it.
3. Armor classes - You need to also have 3 armor classes, Weak, medium and heavy. The heavy armor would be able to take alot of damage but it's gun and tank itself would move slowly. The advantages would be it able to take alot of damage.. but the downside is smaller weaker armored bots could run around in circles making it hard for the bot to fire @ it . The medium armor bots would have decent speed and the gun would move decently fast and the weaker armor would take the most damage but would move the fastest able to run around tanks.
The end result of this would be a completely customized AI for the bots you control. And would allow for a harder game to be made due to the fact that you can customize each bot to handle different situations.
Also the save feature needs to be fixed too.. it sucked getting to level 7 and not able to save and having an .ocx error that causes it to shut down =(