How to complete shell apartment to finished standard in Gozo?

Its difficult to say as there are so many different variables, and everyone has different tastes and standards. One can realistically spend anything between €18K-€40K,  excluding a Kitchen for say a 3-bed apartment.  Choice of apertures can also make a big difference (wood/aluminium, uPVC) and prices rise if apertures are arched.   Tiles and bathroom fittings  vary tremendously as you can buy tiles from €7 psqm - up to even €100 psqm.   A kitchen could be made and installed for as little as €4-6K, but realistically you should budget closer to the €10-15K mark including basic (as in not high end) appliances.  So there is no easy answer.  Hope this helps. It is best if you get some quotes for plastering, tiling, electrical and plumbing works, and then add on the cost of tiles and fittings, plus kitchen as these are very subjective.  Add on costs for air conditioners (prices vary between €650-€1100) per unit depending on unit size.

Just finishing 3bdrm shellfom in Zebbug  all in including kitchen and bathroom, just to add furniture, approx. 350 euros per sq m, including materials and labour. This was extremely creative and cost conscious  i.e. simple straight  3m kitchen 3500 euros with appliances (no dishwasher), nice shiny floor tiles only 18 eur per m2. Indoor doors 550 each inc installation etc.

We bought pretty much everything ( other than plumbing pipes, electric wires, floor tilles and watertank/waterheater in Slovakia where my wife is from. We brought it all to Malta driving in a rented van, we still saved thousands .

About 10% of total cost plus way  much better selection (100's of eshops)  in continental Europe. I think that close to 400/sq.m could be now more realistic (Dec. 2022)