Does anyone kno if there is any bonus missions like in the first game, cuz i just beat it on sane mode and theres no bonus anything, not even artwork.

well sadly there isnt any really bonus stuff except that you unlock an alt ending after beating it. it doesnt matter what difficulty you beat it on either you are guaranteed this new ending.

*****SPOILER*****

if you beat the final level called "Release Therapy" you will unlock "Personality Clash" or vice versa, also keep in mind that the level you receive as the story ending is random, i received "Personality Clash" and unlocked "Release Therapy" but my buddy had it the other way around so i guess you can say its a bonus mission.

Not random, it's actually based on how 'violently' you play the game. More gruesome executions\environment\gun executions and less gunshot kills etc. Will get one ending and doing more gunfights and stuff will get another.