I've ran into a similar issue as well. I'd love to know if anyone has found a fix for this. For some reason moving around with the joystick set to Xbox 360 mode my frames drop from the max 144 down to 38. Its only when I move the mouse, if I move around with the joystick without moving the mouse the framerate doesn't drop.
It does work fine for me when the joystick is set to keyboard mode too, but I also have the same issue you have where using the cannons on that mode is very clunky. Hoping someone can find a workaround or fix so I can use Xbox Joystick in this game.
(EDIT): I just found something interesting with this game. I updated my Cyborg 2 to the experimental software. In the stable version of the software your joystick is locked to 500 hz polling rate, while in the experimental version you can reach 1000 hz. I've noticed since upgrading to the experimental version I get a bit less lag while moving the mouse and joystick simultaneously in this game. I now drop from 144 fps to 48 fps.
I've also read that this game has an issue with mouse polling rates too. Apparently the game drops packets when using polling rates above 250Hz, resulting in negative acceleration during fast movements. I'm unsure if this issue with the mouse was ever solved but that would explain why this game feels much slower when I look around quickly compared to other games.
