Have you ever played 3D Monster Maze on the ZX81? i heard that was a cool game on it 
Yep that was meant to be one it's best games but I never played it because I couldn't find a cassette player that would actually work with the computer (a common problem), unlike Commodore products it didn't come with its own official cassette player.
The longest game I ever typed in was called 'Swag', it took me about 4 hours to type that sucker in (16k) and only got to play it for about 10 mins because I was told to go to bed
