I can only comment as it affects me with small volume trades.

For example I place an order to buy 2000 shares ( 4 lots) among the current bids at 0.63$.
I immediately get filled with one lot and then the remaining Asks hold firm at 0.64.
So I risk sitting and hoping that the remainder of my bid gets filled or I raise my bid to take the 0.64 asking price.
If I raise then the broker that gives me those 10$ trades treats that remaining trade as a separate trade and it costs me another 10$ just on commisions i.e. 20$ total comission and 1500 shares at 0.64 =15$ more.
That is a total cost of 35$, or 25$ above what I originally intended. Same applies when later I try to sell.
I could have saved 5$ by just taking the 2000 shares at the asked price of 0.64 and saved the 10$ extra comission. Either way there is a disincentive for a small time player to participate.

End result they dictate the price to a small degree until someone with a fat wallet takes them out.