Damaged tiles on shower floor

I am in the final stage of negotiation on a property I intend to purchase. One thing that I am concerned about is the missing tiles on the shower floor. About 20% of the tiles are missing and it seems that the owner sprayed some green paint in the area. To fix the problem, do I need to redo the whole shower or can I get away with redoing the floor waterproofing and tiles only? I assume the waterproofing is damaged once the tiles are removed. It is a double brick single-level house.

Refer to the attached photos for more information. Thanks

 

Must be colour blind.

 

You can do one of three things.

1: use as is.
2: replace floor tiles only
3: replace the whole lot, either before or after options 1/2 don't work (99% chance they won't adequately fix the issues).

Cost:
1: free
2: $300-1000
3: $500+

 

Retile the lot I reckon.

 

The house is built on a concrete slab and the walls are double brick. Does this make waterproof less critical?

 

It'll still leak through the walls.

 

Its a hopeless defect with potential building impacts.. Seek advice and a repair estimate. Its not deductible as an initial repair

 

Not at all unless its a acquarium