Sportium
Sportium is a calm, mechanical nut-and-bolt sorting puzzle. Every level hands you a rack of vertical bolts, each threaded with a stack of coloured nuts, a few bolts left empty as working room. Tap a bolt to lift the run of matching-colour nuts sitting on its top, then tap another bolt to thread them across - a nut only lands on an empty bolt, or on a bolt already showing that same colour on top, up to how many nuts the bolt can hold.
Twenty rigs climb steadily from a handful of colours on a short rack to a crowded shop floor of eight nut colours spread across a dozen bolts, with less and less spare room to manoeuvre. Every rig is generated from a solved rack and scrambled by genuinely legal moves, so nothing is ever a dead end - and a built-in checker proves each one solvable before it ships to a level. Make a bad thread? Undo takes it back with no penalty, and Reset returns the rig to its starting layout. There is no clock to fail and no way to truly lose - only a cleaner solve to chase.
Clear a rig quickly and without wasted moves for three stars and a coin bonus, then spend those coins in the shop. No pay-to-win, no fake awards - just a steel bench, a set of bolts, and a clear head.
Sportium - sort the nuts, clear the rig