One of the most classic tower defense game series.

Really fun for a few dozen hours, but after that it got extremely repetitive and frustrating.

i live for this kind of jank. superb, no-frills tower defense with a nice progression system. awkward difficulty scaling after the 10-15 hour mark. depending on which stage you pick it'll be impossible to win or utterly trivial. there are handicaps to help with this, but you end up playing trial and error with each stage to keep it tuned as a challenging but fair experience.