I liked it, however it feels like there is no need for you to swap to the character holding the gun unless you want to do some shooting yourself.
I like that you need to stick together for you to get infinite ammo so that you can keep on shooting, but the character shooting for you almost turns the swap character functionality useless.
Perhaps giving some kind of advantage in case you are controlling it would be better, or maybe make it weaker when you are not the one controlling, so as to have a reason to swap. I went most of the game without swapping, as he obliterated every enemy besides the worms.
Unless of course, the swap was done only in case you wanted to do some shooting.
Anyways, I left my rating. Congrats on the game :)