Axiom Verge is one of the earlier metroidvania type games, before the genre exploded. It might be slightly incorrect to call it a metroidvania though, as it's clearly a love letter to the 2D Metroid games - not nearly as good as those ones, but that's a high bar that few in the genre have reached

Game elements are pretty close to classic Metroid (almost too close), but there's a particular focus on weapons in this one. Not unusual for a metroidvania, or even a Metroid, but tradition generally states that new weapons should double as new traversal abilities. That tradition is followed in Axiom Verge with the first few weapons you find, but it quickly falls back to more expected abilities (high jump, grappling hook, etc)

Eventually you find so many weapons that they're more of a collectible than traversal tools. At a stretch, you could say different weapons are more useful for different enemies or areas, or even just a player preference/expression thing. I kind of wish they stuck to the weapons as tools concept though, and focused on a few well designed ones, rather than including all the ones they did

On its own, Axiom Verge is a pretty good game, but putting itself so close to Metroid doesn't draw a favourable comparison..
Although, to be honest, "Metroid love letter" is what sold me on the game to start (and probably many others), so maybe the devs are a few steps ahead of me here…