Given the big swathe of posts about bad behavior from big companies, I figure we could counterbalance that with some positivity about stuff the smaller guys made that often costs us less too.
The OG. The fact it was all done by a single dude blows my mind. People often praise Toby Fox for the same reason, and he definitely deserves it, but he wasn't good at programming. Pixel was good at everything: programming, music, writing, and art.
Cave Story really isn't a metroidvania. The path splits at points, but there's very little choice where to explore. It's just a platformer action shooter.
My favorite metroidvania has to be Aquaria. Vibes of the game are on point. The story is great for a game in that genre, and the traversal and combat are unique and tons of fun. Soundtrack is phenomenal.
Check out Gato Roboto if you want a metroidvania similar to Cave Story!