The scripting language looks like it would be more cumbersome to use than C.
> Executes one line of script per frame (~60 lines/sec).
Makes the "runs at 60FPS" aspect of the engine feel a lot less relevant. At this speed, anything more complex than Pong would be a struggle. Even a CHIP-8 interpreter is usually expected handle a dozen or so comparably expressive instructions per frame.> Up to 128 script lines per program
I like the idea of on-device programming like this. While I haven't used it, I know there is a DSiWare application Petit Computer that lets you implement more complex (sprite-based) games in a Basic dialect: https://en.wikipedia.org/wiki/Petit_Computer. As DSiWare, it has an official video trailer: https://www.youtube.com/watch?v=4AYlEo3rJHs.