Hmm... I think the placement of the spikes could be a factor as to why I felt the way that I felt. One thing I would try (but feel free not to) is make the spike's hit box only one pixel wide, but the full two pixels tall. I never felt like I couldn't jump over them more so that I felt like I'd hit them when jumping a couple pixels away from them, if that makes sense. It's always interesting how as gamedevs, we always make the game more fair than fair, but somehow even more lenience is required than originally thought.
Just want to reiterate though that I thought the game was very enjoyable as a whole, so good work!