The phrase "unskippable cutscenes" refers to the parts in video games or movies that you cannot fast forward or skip. You have to watch them, whether you like it or not. Full definition
It will not be long before we are bombarded with unskippable cutscenes filled with pretentious drivel, pointless quests that excuse themselves as being trenchant political commentary. (gamesetwatch.com)
This one kills that wonderful atmosphere with long unskippable cutscenes. (retrogamingmagazine.com)
The insistence of cramming story and character into Kinect Sports Rivals is unquestionably a mistake — a galling mix of weak stereotypes, grating dialogue and unskippable cutscenes just getting in the way of the action. (gamestm.co.uk)