I like the game but it would be nice if as you progress you could save the game because it's exhausting start over and over from the beginning. Anyway i know it's a demo and it's a great start. Are you planning to add this option?
The new update tomorrow adds ranks and a mechanic where your lives are carried over to the next level but other than that there are no plans to save progress as there isn't really any progress to save. Both levels are unlocked from the start in the demo (haven't decided if this will be the case in the full game) so if you would like to improve your rank in 1 level you can load it up without having to play the other.