sbenrap: The game still has its wacky moments, but regarding the mutations they are not as severe as in the first 2 games.
Since you have the games, you should just play them (don't let the controls put you off), and be your own judge :)

BananaJane: I've been starting and giving up on mean streets for years, this time it looks like I'm actually gonna see the ending!

hucklebarry: I'm just now playing through the series for the first time... my thoughts below. (wall of text)

Mean streets is rough graphically. Its not a stretch to compare them to the atari. I'm not a visual junky, but this was a tough play-through visually. As far as story goes, it was a good play through. You have to type in all the names and places you want to go. You also have to keep notes since the game doesn't keep track of who you need to talk to or where you need to go. Every location required coordinates to be typed in, so you have to write those down with a good ole fashion pen and paper ;) I played about 80% of the game through without issue. It wasn't captivating, but it wasn't bad either. I finally decided to follow a walk-through just to avoid all the senseless backtracking as after every new lead you aren't always sure who you need to go back and talk to again.

Martian Memorandum... took a few steps back overall. The graphics are much, MUCH better. You now have mouse support (although its very sluggish). The game remembers your new leads and you no longer have to keep track of coordinates for travel (good call here, I didn't care for the travel system in MS). The story was ok. Where it got frustrating was the "puzzle" system. I put "puzzle" in quotes because you aren't really solving anything... just keep saving and reloading and eventually you can get past all the GOTCHAS that have absolutely no clues to help you avoid them. In one conversation you get the option to say one of two things (paraphrasing): 'You are dumb' or 'you are stupid' (again, I'm just giving an example). Picking one means you don't get the information you need, while the other yields what you want. However, if you aren't following a walk-through, you won't know you missed something until, potentially, much later when you get stuck. Then, when you do find out what you missed, you better pray you didn't save over your last save BEFORE that conversation... because if you did, it means you are starting the game over. There are no context clues to help you avoid game ending situations.

Then you get the insta-deaths. Again, with no warning, you can simply die. Open that locker and find a key card, open the other locker and a poisonous snake will jump out and kill you. Hopefully you saved your game before you opened it. My favorite part (sarcasm) is 3 rows of rocks. Pick one, because each one is identical, and if you are lucky you will live. if you picked the wrong one... dead. But, lets say you get lucky, the next step has 5 options (only one will allow you to continue, the rest will all kill you). There is no map, no hint, no clue... you just keep reloading or reading walkthroughs until you get it right.

When you get the vents... I HIGHLY recommend just using "Insert+O+any cursor key (⇑, ⇒, ⇓, or ⇐)" to bypass it. After 30 minutes of running in circles in the single texture maze... I was about to quit since no walk-though could tell me the exact steps to take to finish... luckily I found the little built in cheat to bypass... seams the devs didn't even want to figure that one out too many times :p

From a gameplay standpoint, MM doesn't get anything right. I'd actually label this one on the bottom of the adventure pile in terms of value.

If you want to play this one, I recommend a complex save pattern using multiple files that overlap (because you can easily break your game by making choices)... or, simply play step by step using a walk-through for the story. If you choose the save option... be CAREFUL! Every time you die, the game starts over. You then have to LOAD a save to keep going. You can actually save the new game over the old save if you aren't very careful.

Now! The third game in the series... (Under a Killing Moon)... has me in heaven. Fully voiced dialogue, response options seem to be unique, FMV element, 360 exploration, story is already very intriguing, interface is intuitive (and actually very advanced, even for today's standard), etc. I pressed on with the series based on its reputation and I'm glad I did. UaKM is what I have been looking for in an adventure game. I'm very excited to go further into the series now that I'm seeing some great payoff in gameplay.

So, are the first two worth it? They established a bit of character, but I'm not sure they did much more than the intro did in the third game. There are a plethora of walk-throughs to follow, I would recommend using those if you want to give them a shot. I'm glad I played them, but they were essentially a means to an end... the game I really wanted starts at number 3 ;)