1. Walking through doors is hard, even without staircases: Proving PSPACE-hardness via planar assemblies of door gadgets;Ani,2020
2. Tetris is NP-hard even with O(1) rows or columns;Asif;J. Inf. Process.,2020
3. Pushing blocks via checkable gadgets: PSPACE-completeness of Push-1F and Block/Box Dude;Ani,2022
4. 1 × 1 Rush Hour with fixed blocks is PSPACE-complete;Brunner,2020
5. Block Dude puzzles are NP-hard (and the rugs really tie the reductions together);Barr,2021