I am no Luxur, but they are pretty OK. *Very* M&M-ish (read 3-5), up to silly humour (imagine zombies and ghouls attacking by vomiting at you). Some verbal, trap and maze-based puzzles, also the Xeen way. OKish game mechanics, more advanced than M&M (with a bunch of skills to develop).
Unlike M&M, these are heavily linear though, a hardcoded sequence of separate maps rather than a fully explorable open world. The almost only case where you could choose between 2 locations to visit ended up temporarily giving you some ridiculously powerful megaweapons, and forgetting to remove them once you leave, making the rest of the game a cakewalk (that was in YT3, I think - some astral plane level in midgame).