All the spikes in rough chronological order. The first row shouldn't be a problem since the red spring takes you directly over them, and they're against a platform anyway. The third row is really hard to land on at all. The fourth row is only a tile wide. The fifth row, again, you are automatically taken over by a spring(flower). I will concede the last row, and do plan to fix up the ending to be less ridiculous... the ones I'm most concerned with are the second row, amidst the waterfalls, but I do feel that they're somewhat justified since the player, in jumping over them, is actively not choosing to take the downward route which doesn't necessitate that jump. Or is it not obvious enough? Please let me know where my assessments are off.

"The green newtrons are annoying too, sometimes they're hardly possible to evade (the one in Act 1 by the pendulums)."
If you mean the one you think I mean, I don't see that as a problem, since its firing interval is completely regular and it's totally possible to predict when it will fire, land on the platform, and kill it before it has a chance to act.

I'll consider ammo (although raising it to JJ1 levels is ridiculous -- you'd never run out of anything), and see if there are particularly inappropriate enemy clumps.