Hi CC, good to see you again! In Tidalis, we have the main adventure levels, and then we have puzzles in addition to that. The adventure levels are all randomized, but the puzzles are 100% static. The puzzles are like the puzzles in tetris attack, versus the action modes there. Or same thing with the static puzzles for unlocking side stuff in puzzle quest, versus their main action mode.
In other words, the things we call puzzles are actually sort of block-based brain teasers, with no falling blocks or incentive to click fast, etc. You usually have to meet some objectives in a really small number of moves. Personally I find those overly hard, here and in other games but here as in other games the main content is more action-y and thus randomized.
Even if you beat the adventure itself there is still quick or custom games, which in some games would be all there is, period. You can set up those exactly how you want, and then the seeding is utterly random. There is also a level editor that let's folks create either puzzle levels or randomized action-y levels.
If you're crious, the demo is out, and really fun. Thanks for your interest, and stopping back by!