I've put it off long enough...

I unfortunately won't be much help with publishing info or sound.
Or maybe anything, but what the heck..

I had to use GameMaker for my work experience not that long ago to make an endless runner for a company exporting their games to HTML5 and using them for a games portal of sorts.
Playable on browsers and mobiles.
The resolution was I think 320 x480 I'd have to dig it out to see for sure.

Honestly I found Unity 3D easier to make my first 2D game in, even with the added axis to worry about and no experience/knowledge at all in programming.

With GameMaker(couple months after my 2D game) I had a lot of issues getting to grips with the drag and drop and mixing drag and drop commands with executable code.
I presume you have used GameMaker before or something similar though.
My experience with Unity was that once I got a hang of the extra axis, it was much easier and simpler to read code and organise the framework.
Also I made loads of use of the particle systems to make the game look good.
And just generally using GameObjects was very easy with Unity.
My very first game ever was done in Unity and I was learning from scratch as I went(made it in 3 weeks).
It was much better and more advanced than my later endeavour with GameMaker by far, which was made in the same amount of time and riddled with bugs.So much so I had to restart in the last week!


Sorry for the waffle there, my reason actually for posting was to do with you sprite art.
I was wondering if you have access to 3DS max? Or a similar 3D program.
Might also work with Blender which is totally free(but I have only done this in Max so far).

You can create models and animate them there, using lighting etc.
Then use the viewport to position the camera at any angle you want.
Then I render the viewport (after the render is cropped/clipped to just around the object) out as a png with alpha layer.
And I was able to load it straight into Gamemaker to create a high detailed animated sprite.

If your character is a humanoid you can use Mixamo.com to auto rig a t-posed character model under 22k or so polygons. import to 3D program with a choice of like 3 animation (one being a handy zombie running anim!) and then render out the frames.

I would say once I got the hang of it properly I could from scratch create a very high detailed animated character animation from any angle.
The model I took form my student version of mudbox.But you can make your own or find free ones maybe.

Just a thought if you are wanting to go the route of a high detailed game.
Same can be done for backgrounds and other object sprites, using a 3D program...but i suppose this all depends if you can do a little 3D or just have already a fast way to make 2D sprites animate.

Anyway This might not help you, maybe will help someone in the right position ..sometime..

Good luck on the project
Keep us updated!

Ah GameMaker, yes.
I had to learn that after college to do an endless runner for an advertising type company.Games and brands basically.
I spent ages trying to figure how to get the damn collisions to work properly.
Character would fall through the floor or platforms or even sometimes when it jumped and landed again it would land into the floor and the next time slightly lower again.
2 week work experience turned into 3 to get something done at all.
And because Gamemaker was drag and drop and some code to do what I needed the game was really buggy.It ran ok but porting it to HTML5 for the website brought the bugs out where they werent seen before.

In the end, I had just the last week to do a really simplified version and was very annoyed I couldnt get anywhere near the one I did in C# on Unity while learning to code at the start of college.

Not to say Gamemaker is bad!
It's really handy for prototyping especially and can make decent games.
Great place to start out and probably just didnt suit me, I liked it all code.To me that was actually more simplified as I can read whats going on using monodevelop and tab between only a few scripts quicky. copy pasting code.
But the coder using it was coming from a C# background and said after a while you do learn to work around the bugs that come with it.
Probably the same with all drag and drop type 2D engines.

One handy little code I got off the coder there with Gamemaker for that platform issue was using y= ystart; so the player couldn't go past that point.
Originally I was using

 if(place_meeting,x,y+1,obj_platform)
{
    vspeed = 0;
    grav = 0;
}

with the if statement and that y+1 i had learned developers sometimes call a collision one or two pixels before actual contact, because if the room speed is too fast or object is moving too fast, the code hasn't had time to detect the collision by the time the object has past that point and causes issues with falling through.
Was using at one stage y+3 to try fix it and driving me nuts..

Possibly what you spoke of above with TGF?

Something maybe will come in handy if you haven't seen that before.
Sorry if this is all too basic for you.Mah brain is fried with so much on lol
Finding it hard sometimes to judge situations with others here sometimes...
Hmm on that note. sleep....soonish

Game looked great too by the way.Nice sprite art and use of particles.

did you try Deviant art? Apparently a lot of artists on that looking for opportunities to use their work.maybe a lot of dodge available immediately but then maybe you can get lucky and find a student for portfolios?