Gunman Clive collection is a really enjoyable game. It plays well on Switch and if I remember right you get 50 diverse levels for the price. The levels are divided in arcs of 5 with each 5th level being a boss fight.
For me Gunman Clive was a trial and error experience as it is the sort of game that will require you to remember what comes ahead.
It offers different difficulties for all skills and speed run opportunities.
My personal favourite is Gunman Clive 2 for the more diverse graphics and locations.