It looks very good. Just some things:
– The movement speed could be slightly faster. All the characters look like they are "slowly running" when you move
– If you jump in an opposite direction (e.g. face right, jump, hold left arrow), the sprite doesn't change to reflect that (= you still face right)
– Jumping on lava tiles kills you, OK, but jumping on platforms elevated from lava which look safe harms you as well (which means insta-kill for the archer)
– More ways to regain health would be neat. There's the priestess, but I only found one and it was quite complicated to reach her
– I was really thrilled when I found out the "zombies" can climb. Great job on that!
– If you run out of lives, you are instantly taken to the menu without even seeing the "You're dead" message. AND (!) if you start a new game then, you die instantly with your NEW character and appear at a checkpoint from you previous playthrough
But most important of all; I think the game could really use some sort of hinting where you need to go. We've got the map, which is fine, but it shows all the stuff you will eventually need to collect and with the world as open and vast as it is, you can wander in +- six directions, each of which forking into more paths.
I started the game three times and didn't even find the water shoes. Yet I wandered through many different environments, found three items I couldn't reach yet, killed plenty of enemies (which didn't cause a trouble) and eventually got killed by lava or acid (which caused a lot of trouble) when I reached a dead end.
You don't have to point out a specific glowing X on the map, but you could add some more natural obstacles in the directions that shouldn't be explored yet (for example a "lake" which requires the blue shoes) – early, not after you go the wrong way all the way up/down.
Overall, I am glad I tried out the game. It has really neat graphics and animations, three different playable characters which is always a plus, and it can keep you entertained for quite a while; so my biggest complaint here is probably the navigation.