Pro:
- A cohesive, believable world created by only one person
- The distinct and recognizable art style
- Functional shooting mechanics and fun boss fights
- Well-implemented save points and save system
- Fresh ideas for map traversal and power ups (compared to other Metroidvanias)
- A surprisingly complex plot with tasteful cutscenes ...

Contra:
- ... that is mostly implemented with endless, boring dialogue
- Most weapons are useless and weak compared to the starting gun
- No autofire!
- Clumsily implemented dodge and drone mechanics
- Frustrating difficulty spike towards the final third
- A barely useful map with only 2 markers and no guidance system
- No warp system means endless backtracking
- Content locked behind random pickups and opaque password system
- Grading musical themes without character
- 10 hours playtime feels like twice as much

Magic Moment: When the tedious final fight just kind of ends without fanfareand gives way to a deep feeling of never having to play this again.

Verdict:
Somehow, Axiom Verge has become something of a classic Metroidvania over the last few years. I played though this again to prepare for its sequel and found it to be boring, difficult and simply unfun.

Don't play it, there are loads and loads of better Metroidvanias these days ... I will certainly never replay this.