Vivid Knight is a surprisingly interesting result of what you might get if you smashed a roguelike with a gacha game, and wrapped it in a mobile interface. It is not micropay/time-gated in any way (outside of meta-progression grinding), despite of how a lot of mechanics sound like they are.
So you're in a dungeon with automated movement from room to room (pick which exit), with various things in each room, ranging from mana(steps), loot, vendors, and semi-automated combats. New units are the main loot, and, in good ol' gacha fashion, three of the same type upgrades it, with three upgraded versions to their max version. Each unit, in addition to their assortment of standard stats, has a unique skill, color, and mark, with increasing amounts of the same color/mark giving stronger buffs. This mechanic ties directly into the upgrade system because a T1 unit only 'uses' their color/marks while in the active party, while T2+ can be in reserve. Adding to this mess is a very finite party size-- the starter character only has room for a party of 6, with 5 reserves before you start paying movement penalties, turning a dungeon run into a balancing act between active units that may be at T1 because your T2s are sitting in reserve so you get buffs, and deciding if it's worth wasting roster space to try to get extras to upgrade to T3 while wasting potential buff space in your roster/taking the penalty and hoping you don't end up dying from it down the line.
If that sounded like a bit of a mess, it's because it is. There's a lot of interlinked moving parts and you're effectively trying to assemble a gamebreaking combo before the difficulty curve catches up.
And the not so good: By its nature, it's kind of RNG-based. Accessories have random color/marks, and the getting a good one early can give a huge boost. Meta progression usually means diluting the pool of units so it's harder to get good ones. For some ungodly reason, game speed is part of the meta progression. 33/80 unlocked so far, and no luck. Meta progression is kind of slow-- 3 unlocks for finishing a dungeon the first time, but after that... the 'final' dungeon got me 3 after ~95% completion and two hours. (Need that speed up...)