OK please read this before you try the game:
It has a little accumulator meter on the left that you need to fill up by getting wins with dwarfs in them, it takes about ten wins to fill the meter which then fills one of seven "golden minecarts"next to it.
When you trigger the feature (three bonus symbols in center reels) the accrued "golden minecarts" will each give you an individual dwarf power, such as walking wilds, random wild etc.
So you would naturally assume more carts = better feature right? Wrong; the carts make no difference.
I found this out the hard way:
Deposited $225 - @ $2 a spin it took over 450 spins to trigger the feature, by which time I had only just got 6 full mining carts.
It's a con- extra carts just give you an increased SELECTION of dwarf powers - it's random if you'll get any dwarf powerup on any given spin of the 7 spins that are awarded or not - for the first 4 spins I had no dwarf power and no win at all - after that I had 3 dwarf powers occur on each of the remaining spins which ended up awarding a paltry 23x all up.
The dwarf powers do NOT combine - in fact, having more carts it could be argued is DETRIMENTAL as there are maybe 1-2 decent dwarf powerups (wild column and extra spins), so you'd be better off getting the bonus with only one cart and getting one of those powers.
I don't normally play accumulators because it's impossible to get your full RTP (yggdrasil are particularly bad with this on their Vikings slots) but this is a whole other level of BS in that it's a completely useless accumulator.
It's shit. I have it in a new release compilation video I'm currently doing. And it's fucking 'dwarves' gone wild if you like Tolkien.