Empty nester's new flat search: quality worries

I thought I knew everything about buying property after all these years, but I'm looking at flats for myself now that the kids have moved out, and it's different. We're considering Sattva Lake Ridge. I'm focusing on smaller units, but I noticed some visible damp patches and misaligned windows in a ready unit. What are the absolute must-check points during a final walkthrough? Anything specific for long-term construction quality or potential seepage issues I should look for? Not sure if minor things become major headaches later.