Thank you to all the beta testers who gave the game a try and shared their feedback with me!!!
Overwhelming feedback from Beta Testers is that they all want more options to fight against the robots. It took me a while to decide how to solve this and after a lot of work I have been able implement upgradeable Sentry classes.
There are 3 Sentry Classes that are upgradeable. Each Sentry type can now be Upgraded by 2 levels at a cost of 30 metal units each time.
Range: 200 meters
Accuracy: 95 percent
Rate of Fire: 12 rounds per minute
Projectile: 50 caliber high explosive round at 800 meters per second
Targeting System: FLIR with predictive targeting that compensates aim for target movement during bullet flight time.

Upgrade Level 1 - Upgrades to Armour Piercing Rounds
Upgrade Level 2 - Double Rate Of Fire

Range: 100 meters
Accuracy: 85 percent
Rate of Fire: 5 rounds per second in 5 round bursts
Projectile: incendiary armor piercing rounds
Targeting System: FLIR with predictive targeting that compensates aim for target movement during bullet flight time
Should be used tactically in close quarters terrain against ground targets.

Upgrade Level 1 - Doubles Rate of Fire
Upgrade Level 2 - Extended Ammo Magazine

Range: 200 meters
Accuracy: 20 percent
Rate of Fire: 10 rounds per second in 1 second bursts, 3 second reload
Projectile: self destructing tungsten rounds at 700 meters per second
Targeting System: prioritizes air targets (drones, bombs, missiles), computes incoming flight path and computes firing solution.
Burst fire spread intentionally increases target impact success rate.

Upgrade Level 1 - Adds 1 Heat Seeking Anti Air Launcher
Upgrade Level 2 - Adds 2nd Heat Seeking Anti Air Launcher

Being able to upgrade each Sentry class allows the player to choose between spending your valuable metal on either upgrading to more effective Sentrys or building more Sentrys. The choice is not so simple. Fewer but more powerful Sentrys means fewer targets for the attacking tanks to focus their firepower. Having more Sentrys spread out the incoming damage allowing more time for repairs. This adds another layer of strategy the Player can use to give themselves an advantage.
One of the hardest parts of making a video game is turning your unique idea into a really fun game to play. Even once the game is coded and stable and all your ideas are working... is the game fun to play? I feel that's where I'm at right now... coded and stable. Making the Sentrys upgradeable definitely makes the game more fun to play. I feel like I'm getting there, thanks to your feedback.
Another popular request is being able to hack the incoming tanks... hmmm... will update you again next week!
https://discord.gg/p62Afqr