I don't know if I'm going to write a full review on Axiom Verge, but the game is just great. So many weapons and upgrades and new mechanics all implemented well and fun to use. Looks amazing, with the colors of the areas constantly changing and never getting boring. Great music.
One minor complaint about the game is that there can be times where it doesn't remind you where to go, relying on you to remember a specific obstacle from earlier in the game that you may not have seen for a couple of hours. This is compounded a bit by a lack of a true fast-travel system, which makes the game feel a bit padded as you have to cross the world back and forth a few times. Post game exploration could also no doubt be helped by a fast travel system, no reason they couldn't have thrown it in during the final third of the game.
4.5 Diamonds. Better than Metroid.