I played this when it first appeared and meant to write a comment. I just had another go, getting as far as 48% this time, so thought I should really write something. I'm a fan of exploration games, so I like these classic "arcade adventure" type games, and this one keeps tempting me back for another game every now and then. This isn't meant to be a review, incidentally.
One thing I particularly like is the thought that went into deciding when the monkeys should throw spanners, taking into account where the player is likely to enter a room so as to make it possible to enter without dying immediately. The dynamic with the spanners is cleverly used on some screens where the monkeys appear to be walled off, giving you a false sense of security, yet you are still vulnerable - not something you notice until a spanner suddenly comes through the wall!
Like a lot of other games in the same genre, it can be a bit unforgiving at times, with a few places where the jumps required are tricky and the penalty quite severe for dying. I think I'll have to try using saved states in BeebEm at some point just to consolidate any progress I make.
All in all, another nice addition to the Beeb's repertoire of games, and great fun to play.
. Unless the game is really devious and forces you to go that route later in the game (hope not!)