When I saw this thread, I only had a vague idea of what Axiom was, and needless to say I wasn't too hyped. But it's not very often a fully finished fan game comes out, so I gave it a go.
Wow, am I glad I did.
So:
This game is fantastic, and has a few huge things going for it: first, the art direction. Fantastic choice in sprites, but most importantly, everything
meshes. The levels feel organic because nothing feels out of place within the level art, badniks and obstacles. I loved the little touch of Sonic slipping on the ice in Glacial Galaxy. I can tell you put a lot of effort in it. Great job!
Also, the music. You chose tracks that fit the zones
perfectly. The tone they gave off was somewhere between Sonic CD's US soundtrack and Sonic 3D Blast (Saturn version) and it pushed the surreal aesthetic magnificently.
The level design was absolutely brilliant. They were fun, with a lot of alternative paths and I loved finding them. Utterly perfect!
There are some problems I found, however:
The delay between hitting a monitor and getting its rings was a little bit too long, which lead to some pretty pointless deaths at times waiting to go from 0 to 10 to save myself.
I can't remember the name of the lava level, but it needs major help. The spin-dash pipe is completely broken. Every time I tried using it, I got stuck inside. I would have had to exit the game were it not for being able to glitch myself back out by random combos of jumping, spindashing and peel-outs. Further, some of the lava pits are also glitchy, a lot of times after hitting the lava, I fell through the collision box and into the pit itself, where I wasn't damaged at all until I jumped back up and took damage from the surface again. This happened on a couple of different occasions. It was a great level aesthetically and musically, with some great design, but it was buggy as all get out.
Framerate issues were constant, and though it never got to be unplayable, it was a bit irritating when it constantly dropped under 30.
Animations need a lot of work; the frames themselves are awesome, but they're very choppy, some refinement is very much needed; it's especially visible in the first boss and Sandy Sinkhole's boss.
There were fairly common collision issues with the badniks.
Minor gripes: I really didn't like Sonic's muzzle color, it's really muddy looking. It would be nice to see a little bit more contrast between light and dark on the flesh colors. But the shade of blue was great
The sound quality of the tracks varied greatly. For instance, the shield get sound was really good, but the invincible stars song's sound quality was disgusting; it could use a better rip.
You good sir, have just made the best full Sonic fan-game I have ever played. With a little refinement on the mechanics side, this game will be right up there with the best 2D Sonics. Great art direction, great music, great design, and best of all, I didn't even know what I was missing until I played it. Bravo, sir, you must do more.
9/10, no doubt at all. A few patches and it'll be perfection!