The game starts to ramp up in difficulty at this point, yeah. It's ok to stop there if it's not fun anymore! The key with the falling blocks though is that they start falling when all players standing on them have stepped off. (So not necessarily when the first player has stepped off). And A-5 requires some fairly precise jumps, so it might be easier to come back to that section later (the "A" section is kind of a bonus platforming-focused area). Thanks for playing though, hope it was worthwhile even if you don't progress further.