This was great fun! Simple and intuitive to control, and the destructible terrain is a really nice touch as an added layer to consider. The range of weapons is good, along with the limited ammo to encourage frequently switching based on what's currently available, and I love the risk-reward consideration with rushing to the centre to get the cannon :)
While I don't currently have anyone to play against, the addition of local multiplayer is fantastic to see, I can tell that this would work really well with friends. That being said, the bots that you've added behave really nicely, with a perfect level of difficulty to present a fun challenge without feeling unfair.
Visually everything looks crisp, clean and instantly readable, with the 4x4 sprites for characters and guns each looking very distinct. I also love the screen shake! Everything feels perfectly designed around the 64px limitation
The new keyboard controls you've added work well, although I'd imagine playing with a controller would be a little easier, and I'd love some way to track score ingame. Didn't stop me having a great time here though!