It's hard to make tier list for me because my opinion often shifts, but overall I think you won't kill me about this one. Did it without any bias, nostalgia or community opinions. I've spent enough hours in those game ( 2000+ across all games) to make it sincere!
(maps are chronologicaly if you are confused)
**it's mostly about vibe, fun factor, replayability, flow and art style**
I like Five very much for example, it's hard and fun with one of best zombie boss ever, but it gets tedious with lack of good wonder weapon and way to kill zombies at 40+ besides very bad placed traps + annoying random teleports