I don't think this has been done before - I certainly don't recall seeing it.

Independent online casino 3Dice has just released their new slot called Industria (Dual Core).
This has a computerised theme which electronic components for symbols, a motherboard surround, superb 3D graphics and great 'techno' music. The bonus feature is from 20 to 50 free-spins with all wins x4, and I estimate this to hit approximately once every 140 spins.

What's unique about this slot (as far as I am aware) is you can chose to bet just on the symbols, or on the coloured spots behind them, or both at the same time. Your bets don't have to be the same for the two options; each has individually selectable win-lines and bet amounts.

The payout on the symbols makes for a high variance slot, whereas the colours are low variance.
So you can chose yourself which level of variance you want to play from high to low, or anything in-between!

Couple of screenshots:-

Indust20fsA.JPG

Indust20fsB.JPG

So far I like it - but that may change when I lose my shirt on it!