I just did a couple of runs of Zero Mission this past week myself, finally getting 100% completion in my first Metroid game. I love this series, not only for the exploration and your progression through new abilities, but also for how exciting routing becomes once you can perform sequence breaks

Hmm... probably a 4? I wouldn't want to mess with you, but you have chill vibes

Almost found myself tearing up at a few points due to how it makes me look back on so many past memories that I cherish while feeling so perplexed about the prospect of moving on and taking another step into a world I'm not sure I was ever quite ready for

While its humor is occasionally a bit lost on me, there's nothing out there that captures the concept of change/lack thereof and how monumental that is within the context of our lives quite like this OVA does