I'm not sure Sudoku Wallet is mixer, since they claim they don't have control over your Bitcoin and use CoinJoin.
P.S. I know they're not being transparent about their system and currently closed-source.
You're correct about them closing their source but the wallet in subject claim to be bitcoin mixing wallet and i also believe they are not been honest when they claim not to have control over the transaction done on their platform when all mixing company dies that..