Followed from _this_week_inrust and I liked your post. Some sections were difficult to parse in English, but overall it's inspiring and motivating for a new Rustacean like me ( < 1 month learning)!
One suggestion is to change the divide function to not introduce the concept of 'static which seems kind of distracting for the beginner audience. Here is an alternative:
fn divide(a: i32, b: i32) -> Result<f32, String> {
if b == 0 { return Err(String::from("Cannot divide by 0!")); }
Ok(a as f32 / b as f32)
}
About game development-- I also dabbled in game dev in the past, using Unity3d. You are right to not attempt developing a game engine from scratch. Too much work, you will never finish a game! Just leverage an existing game engine, and try to make a great game, then another and another!
That said, even though it is at version 0.x.x , amethyst looks totally awesome!