Yeah there was a bug that made the spikes almost impossible, but that should be fixed now though. Sorry about that!
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!