>What went right
The concept of the 2D combo based fighting system, the concept of the main character and his origins, Fidget the Flying Fleshlight.
>What went wrong
EVERYTHING
Where do I even begin with this game? The combat is busted, for one thing. If there had been some Devil May Cry style system to the combos, forcing you to add variance and style to get good combos, it could have been fun, but instead it's just based on the number of hits so the best solution is to just spam the air spin move forever. The Magic just makes matters even worse because the AI has no idea how to deal with it and just sort of dies, including the final boss.
The voice acting should not have been done. It's cringey in the extreme. Just remove that entirely. Thank god it's skippable.
The completely unnecessary, jarring, out-of-place, and sometimes cringey references to other games should never have even been thought of as a good idea, much less made it into the final product.
And of course the story. Ohhhhhh the story. Everything about it is trash, most of all the main villain who has no motivation other than "he's a racist asshole". The one good part about the story is the origins of the main character, but even that was mishandled. You started with an interesting idea: you have an elite warrior who, along with the BBEG's army, is ransacking a village. One of the villagers fights him, and gets in a lucky hit. They both die simultaneously, and are reborn as one soul. But it's such a small point in the story, and is fleshed out so little that it just feels shallow, incomplete, and unnecessary. I could think of a hundred different ways this exact same premise could have been done in a way that makes more sense and feels more complete and conducive to Dust as a character. But none of that happened and you're left with a shell of what could have been an intriguing character arc.
Don't buy this game. I do recommend looking up Fidget porn though, it's not too bad.