What did this game do well? (Answer in a few sentences)

• The game offers a good variety of upgrades to support different playstyles, and I like that the enemies have healthbars to show how much health they have left and also have scaling health w/ the upgrades.
• The game graphic was amazing, it had variety of resources to make the game more interesting. 
• This game was very tactile. I could feel the heaviness of the tank, and differences in firing rates, very strongly. The way little enemies had a kind of momentum was a nice touch, allowing for situations in which I would become stressed out as they approached, then relieved as I managed to dodge them. I played up to a score of 500, focusing on rocket upgrades (since they're "heat-seeking" and penetrate buildings), holding down both mouse buttons constantly and moving around when necessary. But still, play did not exactly become trivial, but rather increasingly chaotic, a welcome escalation.
• There is lots of juice in the game. The tank animation feels really good. The particle effects are also cool.

What could be done better? (Answer in a few sentences)

• The cost of healing could probably gradually increase, since at some point healing becomes trivial as most enemies are worth way more.
• I'm pretty sure the rocket-focused strategy is optimal here, but this may depend on play-style. A bit of a sharper tradeoff could be good. I wanted a bit more of a pat on the back for sticking around so long -- maybe a slightly faster pace / escalation of intensity would make the experience more engaging.
• The price written at the bottom are too small and hard to read, it is also not very clear for me what they are for. Maybe you should improve the UI and add more guide
• The speed of enemy upgrade is not pared with the speed of player upgrade. It would have been better if it keeps up at same level.