Jet Set Willy II (aka Jet Set Willy II: The Final Frontier) is the sequel to Jet Set Willy. Once more each room has its own hazards, such as spikes, revolving razors and ropes. The route through the house must be navigated carefully, due to the multiple entrances to some rooms - this is perhaps the first action game where mapping is an advantage. Another innovation, to the chagrin of players everywhere, is manual protection - a sheet of colour-coded numbers.