Performance was generally smooth, I've only found one issue that I was able to replicate consistently: on level 2, I kept getting a heavy stuttering during the time the reinforcment countdown is active.
Options I've found sufficient, being able to separately change mouse sensitivity for different views is nice.
Although speaking of mouse look, aiming felt off and inconsistent. Most of the time I ended up using the turret view with V which felt a bit better, even in situations where the regular view would be preferable. For the combat, it felt like the turret turns too slow for how fast everyone moves around. Combine that with the weird inconsistent sensitivity most of my winning strategy was to just ram myself against enemies and shoot them point blank, letting the shield soak up the damage and trade out, which I imagine is not the intended way to play. I also wish projectile effects would be more visible, most of the time I was not sure where my shot ended up and what happened unless I landed a good hit and saw the enemy tank blowing up.
Apart from the turret, controlling the tank itself felt nice and responsive, though generally weightless. I've also come across a lot of time the tank jittering on slopes, sometimes sliding off to the side when I park on a slope sideway and sometimes not (my guess is the sliding down occurs when parking on edges of two slop faces?). The tanks also do this weird bounce whenever you ram against something, which also makes them feel too weightless.
I like the looks of the tanks, the environment is pretty sparse which I imagine is due to it being early on developement. My only issue with the visuals was that both alive and dead infantry looks the same from a distance, though I understand those are only placeholders.
Sounds seem fine, only thing that would be nice if the reload sound would be a bit more loud - it gets easily drown out in gunfire and for guns with longer cooldowns would be a good audio clue addition on when you are ready to shoot again.
The UI is good, never felt like I was missing anything, just need to pretty it up, could even go unique tank icons for each tanks if you want to be really fancy.
Even though by the end I felt like it was dragging on a little, the tutorial did end up being very useful, especially once I had to face off against heavier tanks. The only thing that was awkward was having to use Enter to progress with the messages, since generally one hand is at the left of your keyboard and the other is on the mouse. Maybe space and/or one of the mouse buttons would be better.
For the guns balance, I ended up relying on the 47mm cannon as the autocannon, while can shoot fast doesn't really have a pucn to reliably hit enemies. The 90mm is quite a spectacle but way too limiting to be useful - giving it at least some amount of vertical only aiming could go a long way. I also wish that my weapon setup would've been saved between sessions, every time I botted the game up again expecting to have the 47mm only to have to go back to the menu because it kept the default autocannon.