So, I recently shredded through Mass Effect because I didn't have my copy of A Dance with Dragons yet and the lack of it made me want to kill some video game enemies in droves. However, as my copy was coming via snail-mail, I still didn't have it when I finished Mass Effect. As such, I needed more things to kill, and so I loaded up Mass Effect 2 to continue to bide my time by dismembering virtual aliens, robots, terrorists, and alien robot terrorists until my six-years-in-the-making Martin fix arrived.
I had heard that Mass Effect 2's gameplay was rather different, but I was still really struck by a few things.
1. Ammo. There was no ammunition collection in ME 1, due to some applied phlebotinum and handwaving whilst saying the words "Mass Fields." I was totally fine with this - in fact, I hardly noticed. What the inclusion of traditional ammunition in Mass Effect 2 made me realize was that I didn't really miss it in ME 1. In certain games, yes, scraping for ammunition is part of the fun. Making that last sniper rifle shot really count is critical. Running out of ammo is scary. But Mass Effect had offered a reasonable-enough explanation of why you had infinite ammo, put a different limiting resource on your weapons (overheating), and it worked fine. Fight dynamics were more like an RPG than an FPS, in that they weren't about limited, unrenewable resources, but instead focused around cyclically available resources. You could play the long game in any fight, because you could wait for your heat to drop, and once it did, the gun would work again. I'd be annoyed if a hard-boiled FPS like Gears of War or Call of Duty removed ammunition, but Mass Effect, like World of Warcraft, really didn't need it, and it's kind of a hassle. Let Hunters make their own magic arrows - it isn't going to unbalance the game, anyway. In works of High Fantasy (and ME, like Star Wars, is basically High Fantasy IN SPESS), such abstractions are totally reasonable. In ME 2, at least so far, however, your two resources (powers, which are cyclically available, and ammo, which runs out) work differently - which kind of makes powers better for my more conservative, calculating playstyle. The other irritating thing is that I end up using guns I don't really like, since ammo is universal but apparently not transferrable. This is a minor gripe - there is tons of ammo, and it is universal. Thank god.
2. Visible HP. I'm not sure why, but ME 2 decided to go to the Gears of War-style "red marks appear on your screen" hit-points for your own HP instead of the previous Halo-style visible Shields and HP. This particular change makes the game feel MUCH more FPSish, since it's harder to keep track of how you're holding out in a fight, or how much damage specific enemy attacks are doing. This also slightly changes the strategic aspects of the game - you have to ballpark things, which is much more of an FPS trait than an RPG one. Enemies still have HP bars, so that part remains largely unchanged.
It's interesting how, despite the mechanical gameplay being very similar, these two minor changes really shift it from feeling like an RPG-FPS hybrid to an FPS.