Cube Bounce

Nice idea.

Maybe you can add more items, e.g. nullifying the game over penalty once, when the cube hits the ground, and gets blasted into the sky. By the way you can also add random modifications, like the cube's velocity changes all of a sudden into a random direction, excluding down or up, to avoid cheating by abusing the edges for infinite bounces.

Also the first-person-view is not an ideal point of view: Most games of such genres use third-person-views, because it's a lot easier to control the character.

Also more stages with varying difficulty depending on the amount and overcoming obstacles. Obstacles may be holes in the ground, blocks, etc. There are many ways you can expand your game.

What I recommend the most is applying textures or any kind of art style to your game. This type of games always have a grand potential for becoming really fun.

Wish you success :)