Mass Effect (PC)
I had already completed ME2 and ME3 on the PS3 many years ago, but had skipped ME1 because it hadn't been released on the PS3 at the time, and wouldn't be until the ME1-3 collection came out. I remember really enjoying ME2 (ME3 less so), but for some reason even though I've had ME1 on Steam for years, I never really played it.
I've put a few hours in, and I must say that I really like it, probably even more than ME2 so far. It's got a very different atmosphere/mood compared with ME2/3, with ME1 being like a low-mid budget 70s/80s sci-fi movie and ME2/3 being like its blockbuster sequels released 20 years later.
I also like how the game opens up after the first couple of hours. You're free to explore the galaxy, and can even land on some planets to explore. There's not much to find and the accessible portions of each planet are tiny, but it's just enough to make you feel like you are exploring space. The exploration, together with finding "treasure" (equipment upgrades, new equipment) in the combat sections makes ME1 feel a bit more like an RPG than the other games in the series.
I have some minor complaints so far. Animation is generally poor, and I have experienced some minor graphical glitches here and there. I've also noticed that a lot of the clothing textures are very low res (even with the texture LOD "bug" fixed by editing the ini file). The choices on the dialog wheel also sometimes don't really reflect what you end up actually saying. For example, I am playing as a "renegade" so I typically choose the asshole responses. When I finished a mission for the Asari consort, she rewarded me by giving me some kind of prophecy, so I answered "Is that it?" (I also know that there is this weird fetish for the Asari all through the series and I wanted to avoid it). I thought this would be taken as written, but the game assumed I meant "let's have sex" and played a little sex scene. Pretty lame.