We've discussed at length how bad The Callisto Protocol PC version currently is due to stuttering issues caused by Unreal Engine shader compilation, and now Digital Foundry has doubled in with their in-depth video analysis. Alexander Battaglia explained:

　　The Callisto Protocol on PC is unfortunately disastrously poor at launch. There are many issues with this game on PC, but the most significant issue is that The Callisto Protocol on PC is an Unreal Engine 4 game that does not pre-compile its shaders, so like nearly every Unreal Engine game I reviewed in the recent years that means Callisto protocol on PC has awful shader compilation stutter. Every single thing done in the game that is new or shown for the first time induces massive stutters. The opening of the game was almost comical with the frequency and severity of the stutters from shader compilation. To sum it up, shader compilation stutter absolutely ruins The Callisto Protocol on PC and any attempts the game has to try and build mood or engross you in its story. [...] It's important to point out that lower end CPUs will have even longer pauses and stutters when they show up. A massive 400 ms stutter on the Core i9 12900k, for example, turned into an even more gigantic 750 ms stutter on the Ryzen 5 3600.

　　That's not the only issue with The Callisto Protocol PC, anyway. According to DF, the game is also CPU limited, as we had also surmised while testing.

　　If you do somehow manage to stomach the stutter on PC, you will also be confronted with other problems. The Callisto Protocol is barely saturating the CPU in moments when you are CPU Limited in this game, so it is very single thread limited, apparently. This is a lot like Gotham Knights, another extremely troubled Unreal Engine 4 release. 

　　It's not all bad, as the game does look very good with everything maxed, and the sound design is noted as excellent. Still, we can only hope that Striking Distance Studios and every other game developer using Unreal Engine for their game takes a cue from Sumo Digital's decision to promptly fix the launch stuttering issues of Sackboy: A Big Adventure on PC.