This was a tough one.
The new traps are good addition (too bad you can't use them in the base game). The artwork, as always, is fun and kitschy.
The script is much of the same self deprecating humor from the base game and it's three of the same voice actors so if the base game was your jam script/voice wise, then you'll like what you'll find in this expac. Thematically, well, it's a Western but doesn't seem to draw from much specific Westerns except for as a naming convention.
The maps are poorly balanced (same old issue of random events triggering the release of mobs that are pretty much invulnerable with heals). I'm not a fan of this "gotcha" style map design, preferring challenging, but achievable goals. The levels crash frequently. There are a lot of bugs (some that are carry overs from the base game) that make it difficult to enjoy (random double clicks or not recognizing clicks at all as well as certain buttons not being recognized when pressed). The mechanic for apply perk potions to troops is simply ridiculous and really needs a more user friendly method implemented.
Final take: I probably wouldn't pay full price again, but would snag it at a significant discount like 60%+ on steam sale.