Same here. I was actually enjoying it until the first spikes. Then no matter how quickly I started crossing them, I could never get more than 3/4 across before they came back up. Don't know if there's a trick I missed or what, but that definitely feels broken.
Yup, that's fixed it. Thanks. Haven't found the secrets yet, but the game is beatable now.
Don't know if the guns are really adding much. I pretty much never had to time any of them. Not sure if that was deliberate or not, since I know there is a slight gap in their firing after a fairly long delay. The only one that gave me any trouble at all was the one beside the double-jump, and that one stopped being a problem when I finally started thinking to make sure the double-jump fired before moving right.
Otherwise, a lot of the timing actually feels pretty solid!