A bit unfair this - either the game is fatally bugged or I have something untraceable in my Beeb that this game dislikes!
Nothing more or less than an inferior copy of Acornsoft's old classic Monsters, you must dash up and down ladders digging holes and filling them in when the monsters fall in.
Trouble is - my copy doesn't allow you to dig any holes, making the game a little difficult and pointless to play! Update next month if I manage to get a working copy from Atlantis.