HITMAN World of Assassination on Steam
store.steampowered.com
Enter the world of the ultimate assassin. HITMAN World of Assassination brings together the best of HITMAN, HITMAN 2 and HITMAN 3 including the main campaign, contract mode, escalations, elusive target arcades and the roguelike inspired game mode HITMAN: Freelancer.

Treat Part 1 as a very beefydemo. Even by itself, it’s a great 10-20 hour game. If you love it, get the Standard Edition.