Spoilers btw, download it and then play it before reading this review. 
Gameplay wise, a bit tedious. You place random stuff with no clear objective, sometimes you can get stuck in walls if you jump, the sound design is alright, although a bit repetitive. the movement of the... player? of the villain is a bit slow and clunky, which yea makes sense but makes exploring a bit slow.

But the story? 

You boot up the game, watch the cutscene, and if like me, you didn't read the description, are a bit confused that you are playing as the villain. you try the first jump, fail, and a familiar voice talks to you. Its clear that its the lead dev from the cutscene. You all that stuff in the beginning, and  then are led outside, to place... coins and stuff. The objective serves no purpose, or none that I am aware of. You try to interact with the sign, but it does not say anything. The dev is still rambling about the game, how tired he is. And then you remember what he said. "There's something out there. I promise." Or... something along those lines. You see the statue behind the castle. You try to interact with it, climb it, but there's seemingly nothing you can do. You look off into the distance. And so you walk. You find statue after statue. But nothing happens. The dev doesn't say anything. The statues remain without change. You think it has to do with the strange black figures. But nothing has happened. You pay your respects to the graves... nothing. You try to enter the barn... nothing. You try to give a sacrifice to the eggs, or even to the blood pool by one of them. It remains unchanged. The last... tourist attraction, you could call it, were the houses. You try to enter them, and to your surprise it works. Except theres no collision. Theres nothing inside. They are hollow. Defeated, you make your way back to the castle. Theres nothing else to find. You could spent more time, trying to climb the mountains, with the hope that theres something out there. But there isn't. You enter through the castle. The dev sounds just as defeated as you do. But you remember what one of the npcs said to you. The only other npc. You bang your head against every single wall. But to your surprise theres another door. The black icons meant something. You enter. It's the testing grounds. The one that the dev used to test out everything. And he reveals that Axo Waddle is not coming. Because he never existed. There never was a way out. The game jams deadline is coming to a close. And there isn't anything else to do. You try to interact with the npcs. "Let me go". Forever chained to the castle. "Bouncing will lead to more fun!". But there isn't anything else to do. The game is empty. Signs that say nothing, a slider that does nothing, lifeless enemies, like the statues you traveled to, a princess stuck in chains that can never be undone, and a villain without opposition. All waiting for a hero that doesn't exist. You can place coins, and springs, and enemies. But there's nothing else to do. An endless void. 

So yea. pretty good game, 8/10