That's good to know. Still a dumb design decision to lock levels behind kill count, but it won't be too bothersome if you don't have to deal with it if you play well enough.
It's not exactly kill count, I can see why people would call it that. But really there's a purple "destruction meter" that every enemy unit and structure counts toward, so a ground enemy may be worth 1, a tank is worth 5 and a building is worth 5, and rescuing a civilian is always worth 10, with 10 civilians per stage. If a stage has 0/100 destruction and you complete it, it will count as 100/100 and no amount of replaying that stage will ever help, you would start by replaying the stage with the lowest destruction %. Like I said I had to do this once, either before the second or third boss, and I only had to clear a single level I had honestly deliberately skipped stuff in.
The game never expects you to break EVERY object in every stage, but you should be breaking >75% easily just by being attentive. I haven't crunched the exact math but I usually came closer to 90%, missing a couple of civilians or some enemies I failed to clean out.
For the record I quit DKCTF due to the collectables being far too well hidden and rarely have trouble on a second play finding stuff out--if I missed something it's usually a stray enemy or accidentally going the "right" way at a fork when the "wrong" way has goodies--such a Video Game problem.
This kind of gating seems like a way to reuse assets, which is fine so long as the level design is sold enough that it's fun to play through many times over.
It's more like they want you to try and 100% levels every attempt and maybe speedrun on top of that--there's even online leaderboards, little "all civilians/destruction" medals for each level on the world map, and the obligatory trophies to encourage you to that end.
To that end, I'd have appreciated a dev-set par timer personally--I loved that in Mighty Switch Force, but with leaderboards I get too intimidated. Static dev set times are way less frustrating than the ever changing (potentially) highly competitive speedrun scene.
