I always use this program as the benchmark test. If you've ever owned a ZX81 then you know what it is. It has such a strong resonance with me. The first time it loaded from tape after the tense 6 minutes of FSK madness it almost stopped my heart. And then I played it.

Fast forward 30 years...

Ladies and Gentlemen.

ZXpand.

Allow 28 days for delivery...

...or get one in 10

See previous post for links to further information.