Addicting
Yeah, It's very addicting, but then it gets kinda bored.
I would love more upgrades, more things that may get you further and something that will slow the man down.
I would also like a story in it, like competition to throw it heighest or longest and there will be boss chapters too lol.
By winning you may get special items or powers that you can use at the start or to help get the object further.
Of course you can't overdo it with powers and items, so you would have to maybe choose 1-2 powers and 1 item maybe?
Also add more backgrounds when you get further and also when you get really high, please add background there too, and not just empty background.
You maybe will get a cutscene when you get really high or really far?
Achievements is always fun to have.
Idunno, this is suggestion to get this kind of game better and more phun (yes, phun). PS: You may have other people to kill than just the ninja, like something that will match the background that I was suggestion about. So it had to be like Aliens or something in the space, while some random and funny looking "enemies" to kill when your on the surface.
Anyways, Idunno if you really care about suggestion or will make an another game, but I hope some if this may help in the future.
(I probably got some wrong gramma, but you should be able to understand the suggestion... I think)