I stayed at the Marc apartments 5 years ago. They are situated on a steep incline it would take you approx 15-20 mins from the beach.On a hot day.
There`s two ways of getting to them, if you walk straight up cardiac hill, then turn left at Tropicana suites and walk on to the Marc. This is the most direct way but the steepest incline. By the way cardiac hill is the hill up to Magic rock hotel, it`s behind Burger king.
The other route is to walk on towards the covered market and turn right opposite Dia Dia supermarket and keep heading upwards.
If your returning from the sqaure on a night I`d recommend getting a taxis back as taxis are always available and cheap.
There is also loads of watering holes available on route.
We found the walk back a bit of a pain as we were pushing a pram but it didn`t spoil our holiday.