Exactly how I remembered it, I get the MLaaS splash image presented to me, with the generic "Choose a character" dialogue.

It's not fancy, but it works... however, the verb panel has a collection of actions already. For as long as I can remember, those four verbs appeared at login and were never removed for the professionalism -- the only one that might have any use at this point is who, but even then, it shouldn't appear in a panel already (or at all in the case of just one verb).
After being given an opportunity to name my spy, I appear in a small room.

You also get to hear the MLaaS music at this point -- anyone who has played the game previously will flashback to hacked kiosks upon hearing it, others will just hear a cello lead.
Anyways, in this room you choose the faction you want to join. The publicly available factions are red, green and black, and it is one of these you must choose here. Black agents have access to a ton of weapons and need relatively less skill ratings to use them, and have the best base defense; red agents have access to a temporary stat buff vendor ("stims") and their skills cost less to train; green agents are allowed to carry an extra document, they have a teleporter to get the city quickly, and have a "bug" vendor (for spying/listening in on others). There are also two agencies available for those willing to part with five bucks, and those are purple and whit. Purple agents trade the ability to wear armour and wield firearms for unique skills like pacify (disable all attacking in an area for a short while), sneak (move while hidden; everyone else immediately comes out of hiding when they move), and pickpocket, and white I'm not particularly sure about -- when I played MLaaS way back when, the faction wasn't working yet, and I've yet to meet a white to observe or ask them about their abilities.
There is usually "side reward bonus" on the server for specific factions (which is what the first two lines are in the above image), but I personally have no idea what that bonus applies to, if it's permanent, or even if it works. I chose to be a green agent, since it was the first faction I joined oh so many years ago. Now, I'm sent to the green base.

It seems I've run into a problem -- some sycophant has blocked in the green base (the other factions -love- blocking up green base). To push those boulders out of the way, you need a high strength rating, one that someone just starting can't achieve. It seems that I can't get out, however, green agents have a teleporter, remember? That's what's behind that transparent green box at the southeast corner of the base. Using that teleporter, I can get to the city and circumvent the need to push those boulders out of the way. The faction advantage is working out already!
At this point, I'm at the green city base (every faction has at least two bases) and I'm going to retrieve some documents here. Documents are your entire life as a spy here, considering it's the only self-sufficient way to get training points, and almost every enemy agent wants to get their hands on them. To get some documents, we visit the document clerk.

Depending on your rank, you can carry a specific number of documents. At level 1, it's two for most players (or three for a green, remember), so I pick up three of them and go drop them off. But what's this?

On my way to trying to remember where the North Central dropbox is, I happen across a secret document. These spawn all over the map just like some inventory items (which is where I got the leather boots) and award you extra cash upon successful delivery. You can also turn them in at your HQ for training points instead.

Oh yeah, the North Central dropbox is in the countryside. Anyways, that's basically half of the gameplay -- you pick up documents, and drop them off at the specified dropbox. When there's other players, they hide behind the dropboxes and swipe the documents you were looking to drop off, then go deposit it at their base for a significant reward.
The other item that comprises gameplay with the document running is the item vendors; all of those beige boxes with a picture on them from the city base screenshot are vendors. Each item you can get from a vendor has a "quality" rating which affects its performance. For instance, the leather boots I found are quality 8 with a protection rating of 6, whereas a quality 100 boot would have a protection rating quite high in the double digits. Vendors are susceptible to being "hacked", where use of them causes you to give free training points to the person who bugged it, and I believe you lose some cash to them as well.
Another element of gameplay is missions, with rewards ranging from access cards to medals. If there's one thing Skysaw certainly did right, it was the mission structures -- most of the missions require a specific sequence of completion, and a lot of them require the result of another mission to complete -- safe item mission requires a safe document medal, several missions require vouchers or training papers that you can only get to if the magenta mission was completed, periwinkle mission requires a purple application, so on and so forth. The most important rewards would be the access cards and the security chit, since access cards make life a whole lot easier in MLaaS, and security chits protect your stuff from being dropped upon death or stolen by enterprising purples.
The true glory of MLaaS is in multiplayer mayhem, which opens the potential for hacked kiosks, traps everywhere, shootouts and base raids, spying on people and all other manner of fun stuff. For reasons unbeknwnst to me, MLaaS has faded into obscurity in recent years, and just a few touchups could likely bring people back. It's certainly a gem obscured by its age and lackluster, albeit unique, graphics.
Anyways the game is great with a bunch of players on each team coordinated strikes and other mischief.