Answering only your last question, since I didn't play it. (I sell asset packs on itch and write with AI help, so weigh that.) Would I click it? The 315×250 thumbnail holds up: the title reads, and the short description is the right one. Three things cost you clicks after that.
The cover is a different art style from the game. It's a smooth illustration, while the game and your Pixel Art tag are pixel art. Someone browsing that tag sees a vector cover and moves on. The hero also stands still with their back to us, so nothing says action-platformer. A pixel cover mid-swing in the dome with the planet behind would fix both.
The 1280×720 embed widens the whole page. The column grows to 1280 px, so in a 1024 px window the page scrolls sideways and cuts off the right edge. Use 960×540 with the fullscreen button you already have.
Your best hook is in paragraph three. "Metroidvania with action-RPG loot" opens the meta text, but the page body starts with story. Move that line above "Graduation day".