At such extreme precision, the measurement backaction due to Heisenberg’s uncertainty relation can no longer be ignored. One should naturally be led to the question of whether or not many-body dynamics will be modified and, if so, in what way. We will address this issue by focusing on few-body dynamics and quantum critical phenomena. In the former, the measurement distinguishablity of multiple particles leads to a complete suppression of relative positional decoherence and quantum correlations persist under continuous observation in a manner analogous to decoherence-free subspace (PRA95, 022124 (2017)). In the latter, the measurement backaction is shown to shift the quantum critical point and yield a unique critical phase beyond the scope of the standard universality class (PRA94, 053615 (2017); Nat. Commun. 8, 15791 (2017)). We also find that the propagation of correlations can exceed the Lieb-Robinson bound under such continuous observation (arXiv:1709.03704). Continuous observation also restricts the Hilbert space and the emergent nontrivial Berry phase yields some startling effects such as the Zeno Hall effect and retroreflection (PRL118, 200401 (2017)).