The UI is properly scaled now. I'm playing on a different monitor than last time so I don't know if you actually added proper scaling or not, but I'm glad either way.
I looked like this in the cutscene after destroying the player tank clone in the tutorial, not sure if it's intentional but it made me chuckle.
Beat the first level with relative ease and watched the replay. I still don't understand the point of this but it's neat, I suppose. I would add an on-screen prompt for pressing ESC to exit the replay, I was lost for a second.
You misspelled "independently" in the chaingun description. I picked the landsword (nice) rockets for the second mission, which I expected would replace the coaxial chaingun. Turns out that it goes into a separate secondary weapon slot that you are not introduced to in the tutorial. I had to go into the keybinds to find the binding for the rockets.
I beat the subsequent levels with the 40mm cannon and the rocket secondary. I don't know if you made the game easier or I'm just more well rested this time, but the game feels a lot easier. The third-person view is fun but the sights option is simply superior for combat, I only find myself using third-person when I'm in one of those goofy "drive in circles around the guy" fights or when I'm just coursing through the map.
The railgun doesn't seem to land exactly where I'm aiming, it goes slightly up and to the left. I don't know if you did something to the 90mm cannon but it feels pretty usable instead of just being a meme weapon. It's cool that you can play as enemy tanks, I find it a little lame that you still have access to the sci-fi repair minigame with them but I understand why you made it that way.
I had no framerate issues, whether that's due to optimizations on your end or not is a mystery to me.
Good fun, I hope to see more in time.