Despite gog's claims at the top of the page, it really does affect the single player & you're effectively getting a very limited experience without that constant online server communication. I played this on the Xbox One (free/GWG) & every time the servers went down or shoddy internet disconnected you had to wait for a reconnect or save & quit. No progress made is incorporated if you do ever play offline, even if you have levelled up significantly whilst connected to their servers so you lose all level progress, items etc until you go online again. The following are locked behind the level up system which itself is locked behind the online DRM: Starting locations which also often have a preset disguise are unavailable which greatly limits the replayability & experimentation; sure you can go through the story once with the bare basics (suit, default pistol, piano wire, coins) but a fundamental part of the game is replaying to explore new areas & creative options with the unlockables. Having new starting locations & disguises keeps it fresh & gives you an alternative to running the same starting routine everytime you start the level. Unlockables also do make a big difference with things such as silenced rifles/shotguns unavailable along with lock pickers/electric key hacks and various poison syringes/jars. Yes, some are cosmetic but not everything is. Escalation missions add a huge amount of variety and replayability by offering different targets & restrictions but are also locked out & again represent a key part of the single player experience.
