SAN FRANCISCO — If you want to make a truly killer app, here’s a crucial part of the creative process you shouldn’t overlook: Give your “finished” software to someone, ask them to do something with it, and then shut the hell up.

Observe their interaction with the app, and you’ll learn what you’re doing right — and what you’re doing wrong.

That priceless piece of advice comes from Bill Atkinson, an Apple veteran who coded some of the greatest Mac software of all time, including HyperCard and MacPaint.

Upcoming sci-fi shooter Rogue Invader looks like a massive HyperCard stack in glorious motion. Currently on Kickstarter to fund the last bit of development, the roguelike game is the brainchild of Squishy Games founder Nathan Rees, who’s been making games ever since he discovered the joys of MacPaint as a kid.