Players are reporting a stats debuff to your units in NIKKE: Goddess of Victory if you do not meet a mission’s “recommended power” threshold. This reduction in stats can be up to a 75% demerit, which should pretty much assure you will fail the mission rather than be able to barely coast by. This Reddit thread suggests this penalty can even be as high as 90% if you’re around half of the recommended power due to how it scales. There’s another discussion here about the “power scaling”.
User Razerisis talks about how experiments with teams with no synergy, or not appropriate for a stage, can clear stages as long as the team meets the recommended power threshold.
“Obvious scumminess aside, this means that there is essentially no gameplay to be experienced here. Stages will either be so easy that you literally cannot lose, or impossible.”
Regarding the 75% figure, you can find the image below shared around such as in this Reddit thread. The highlighted points show the unit’s stats at 85k, but when attempting a stage below the recommended power threshold, this is reduced to 63k.
Besides applying the debuff to stats, there are also comments from NIKKE players which suggest the enemies also get buffed, which would further assure failure at a given stage. You can find other anecdotes appearing to confirm the game’s reliance on simply being a numbers game, having one unit essentially carry the squad.
Of course, as with anything player reported, there will be those who say that the core gameplay mechanics still do matter, clearing one stage way below recommended but getting thrashed in another due to a bad team composition.
NIKKE will be having its first event soon enough. We’ll see if the devs will address this “issue” before that happens.