Thanks for the suggestions, johnnydc!
For the first suggestion, it is technically possible to have multiple player profiles, but it's not built into the game. All of the player data is stored in a file called playerinfo.dat in the Cogs directory (The location of that directory depends on whether you got Cogs from Steam or another distributor). If you want to save your data and create a new player profile for a friend/sibling, just rename that file to something like playerinfo.dat.johnny. Next time you start Cogs, it will create a new, empty playerinfo.dat. To save your brother's data and restore yours, just rename the files again.
As for the second suggestion, we toyed around with the idea of having the solved puzzle stay in place until a user clicks a button to start the final animation, but we decided some users would find that extra interaction too slow or awkward, so we did away with it. I'll put a +1 under that feature request.
Founder, Lazy 8 Studios