Yup, it is pretty much intentionally unwieldy. It's not really supposed to be a platformer but more like using your gun as a jetpack to fly around. Probably didn't get through as much as I though it would and will get some players to get frustrated about the unwieldy movement.
You can get up that section, you just need a good jumping start for some initial vertical velocity and then boost up with your gun. It's not easy but shouldn't be overly tight either. That also isn't the only way you can go (unless you've already noticed).