1. Fallout 76 - bugs galore, no NPCs other than robots, lame Radiant quests such as collect bottles, poor engine/asset flip of Fallout 4, waste of time even if it didn't have so many bugs. A game so bad, it was discounted 40% or so the week after it came out. Oh yeah, Bethesda clearly advertised a canvas bag in F76 Collector Edition and instead it is a 50 cent nylon bag found in the $200 collector edition.
2. Playstation Classic - Nintendo has shown how to do it, how do you mess this up so badly? Very poor game selection with many early launch games that had horrid graphics/gameplay and lacking key franchises that defined the Playstation 1, 50 Hz games, games having poor frame rates beyond the 50 Hz screw up, no analog/dual shock controller (just include 1 controller and let people buy a 2nd).
3. Diablo Immortal - has Blizzard learned nothing, if announcing a mobile game of a popular franchise, you need to also have a teaser of a REAL game coming to consoles/PC, especially if it is the centerpiece announcement of your convention that people paid $200 to attend + the cost of a plane ticket/hotel. What makes it even worse is the game is clearly based off a Chinese mobile game clone of Diablo with the same exact interface as the Chinese release.
4 (Honorable mention) Telltate studios going bankrupt due to management incompetence such as insistence on keeping the same broken engine, licensing a ton of expensive properties to put out games that all feel too similar, for some of the licensed properties they removed the essence of the franchise which caused the game to fail commercially (GotG - management thought no one liked the humor and it had to be edgy/dark - huh?????), hiring new people and pretending nothing was wrong until it was too late, not paying any severance/health care to laid off workforce....