I couldn't figure out how to set the cops on fire, and I couldn't find a way to switch weapons either. Maybe using the mouse scroll wheel to switch between weapons would make things easier for new players.
I also found it a bit strange to start with a flamethrower. I'd probably make that the third weapon, with a baseball bat as the first and a pistol or rifle as the second.
The tips were a little hard to see because some of the itch.io buttons were covering part of the game. I think the game might be a bit too wide for the page.
Another suggestion would be a short tutorial at the beginning, with arrows pointing to a few objectives or simple starter missions. I had fun playing, but I wasn't really sure what I was supposed to do.
Overall, it's a cool game! It gives me GTA vibes with all the chaos going on. Nice work!