I believe you need to issue a letter with the various complaints pertaining to the flat and facilities (not the traffic noise).

request that all tiles be checked to ensure that they are all secure requesting for a letter of guarantee that no further tiles will come down. Ask for the bathroom issue to be resolved urgently due to issues of safety. As for the housekeeping, advise them on the poor level.

If they fail to come a resolve the issues, you could try going down to the municipality committee linked to tenancy and lodge a complaint.

From what I understand, they will inform the landlord that you will rectify the issues and the monies associated shall be deducted from your rent.

As for trying to get out of the lease, I am not certain.... try with the landlord verbally.