Well, the game isn't really noticable when your orders have such a huge edge (like willing to pay up 1$).
For you 2-5cts slippage doesn't do very much since you probably trade for points. But think about it what that does to your R:R when you trade for 10-20cts with 5cts leeway. turns a 4:1 into a 2:1 pretty quickly.
I think everybody knows how the "frontrun the customer limit order" game works so I'm not touching it here.
The hidden game, however, is played with market orders/marketable limits, because the lit exchanges have different execution speeds.
Here's the thing: As a market maker, you want to get fills on the strong side and avoid toxic fills on the weak side.
So as a very (very, very) basic example lets look at the SPY and the ES. The ES has a huge order of 100,000 contracts sitting at 2684 and you are making a market in the SPY.
You will quote 1000 shares at 268.20 and 200 shares at 268.60. 1000@20 is your strong side. Even if you get taken out, you'll probably refresh at least as long as the 100k cars in the ES don't disapear.
60 for 200 is your weak side and you don't really want to get filled here, but what can you do? You are a MM so you have to quote, right?
Well, not so fast. There are 13 lit exchanges so you decide to quote the minimum on every exchange lets say 15 shares each. Now a customer comes along and wants to buy your 200 shares by using some kind of smart router by either IB, TD Ameritrade, you name it.
The "SMART" router decides which exchange his order goes to which way it's going to split up and so on. But those things are never synchronous.
The order goes out and hits the 15 shares you posted at EDGX first and since you are so fast, you cancel all other 15 share orders at the remaining 12 exchanges before the SMART router has a chance to take them out.
So the customer either doesn't get the full size or he will be slipped. In your example, you'll probably get 15 shares at 105 and the rest at 105.02
Renaissance has a patent for a SMART router that uses an atomic clock so all the small orders go out at the same time because of this exact problem. You can read it here:
https://patents.google.com/patent/US20160035027
With DMA you can chose which venue you want to route to. When I did equities, I had to learn order routing first. There are extra venues for passive midpoint orders (yes, you can post hidden limit orders between the bid and the offer), then there are SMART routers that are specialized on scraping all the venues that allow posting passive midpoint orders.
There are darkpools, then SMART routers that scrape darkpools, there are darkpools where you can post passive midpoint orders, there are midpoint peg orders... I think you know what I mean. When I stopped, there were dozens of custom venues, darkpools, special routers and 219 (!) individual order types.
In other words, when you go through retail brokers you have access to probably 1% of the options you'd have with DMA.
Or have you ever heard of ARCAPNPB (undisplayed limit order that is priced on the contra side of the spread and becomes visible once the spread trades away from it), BYXMPL (BYX exchange midpoint order), DBStealth (Deutsche Bank darkpool aggregator), EDGXMPM (exchange for trading shares at the midpoint price)? No? But that are some examples of were the business is...The retailer without DMA only gets the breadcrumps.
Since the introduction of RegNMS, the euity markets became a hide and seek game. And I can tell you that the majority of the big volume is done either in darkpools or OTC.
From all the guys who used to make a living with daytrading stocks, only the microcap guys and the "stocks in play" guys survived. In microcraps you trade against retail idiots and in play stocks are full of whales who need to get in or out quickly and don't care about price.
So I'd think really, really hard and long weither you really want to get into that game from the retail side. It's probably even better to trade CFD's against a bucketshop.