If you syringe someone while holding the suitcase, you will drop the it onto the unconscious person, then if you pick it up back you cannot drag the body around anymore.
Permanent weapon glitch
If the player faces a wall then deploys the sniper rifle in the suitcase, then 47 will turn around to an angle free of obstacles. Immediately open your inventory and choose any weapon. Then 47 will be holding the weapon forever as if it is one of the parts of his body (it will not cause covers getting blown).
Instant sniper deploy glitch
If the player deploys the suitcase in front of guards they will open fire. And if you are hit, you will instantly deploy your sniper.
Sunglasses glitch in Rendezvous in Rotterdam
In the mission "Rendezvous in Rotterdam", when you go inside the building, go to the bartender in the bar. You will see him either roaming or standing, wearing red sunglasses and black T-shirt with jeans and he has a golden hair and beard. Go to him and you can either sedate him using the syringe from your inventory or you can kill him. Next take his clothes and press the "F1" button if you're playing Hitman: Contracts on PC or the button in your console with shows the "First Person" view. Now press "F1" and you will see that slowly the entire screen turns red and again if you use this glitch outside the building in the rain then instead of red you may see that the whole screen turning golden yellow. You may enable or disable this glitch using the button that shows the "First Person" view in Hitman: Contracts. This glitch only works if you're wearing the bartender's clothes. The same glitch will also happen if you enter first person view while holding a gift box from mission "Traditions of the Trade".
Dead Mime Alive Glitch in Hunter and Hunted Mission
In the final mission of Hitman Contracts game, Hunter and Hunted level, the location where the mission's target Inspector Albert Fournier can be found standing behind a police van, you will see behind him a crowd of people on the other side of the police barricade. Within the crowd is a mime artist, which if killed will not show up as dead on the map screen.
If, at any point in the game, you hold down the sprint key (e.g. shift) and keep tapping the movement key (e.g. w), 47 starts sliding. This is actually the motion when he stops running, extended by tapping the movement key. 47 will move at a speed which is close to running, but all the NPCs will perceive him as walking. This is extremely useful to save time, and especially in speed runs.