Mass Effect 2 was a game about choices. Yes, it did have aliens, a plot to shake the universe on its very foundation, sex sequences, and an epic soundtrack to tie it all together. But ultimately Mass Effect 2 completely hinged itself on the decisions commander Shepard made. The alliances you chose, the romances you engage in, and even your save file from the last game all played a role in shaping the storyline that unfolded till the very end. However, while Mass Effect 2 did keep many of its promises there was one really powerful storytelling element that was all but absent from the gameplay. Something that Playstation 3's exclusive Heavy Rain has in spades.
Giving decisions to a player and then telling them that they will experience the full weight and consequences of their actions is a hefty promise to make. For a consequence to be experienced, the player needs to genuinely care about the characters. Mass Effect 2 never really gave me the chance to love my team. Sure I collected them, met them, learned about their hobbies and sexual preferences. In some ways I became attached, more for their combat usefulness than anything else though. The most interesting characters are received late in the game (Thane and Legion) and they aren't covered nearly enough, while the useless predictable eye candy hovered about for no particular reason at all (Miranda and Jacob). You learn about them through forced conversation that only sometimes seem to flow, and it's only through the game's cutscenes that characters really seem alive.
As far as character development goes, Heavy Rain is everything that Mass Effect 2 should have been. Players are given the chance to see some history and background into the lives of each member of Heavy Rain's cast, they're given the opportunity to develop a bond with each character. The difference between Heavy Rain and Mass Effect is pacing, and while being a semi-linear storyline gives Heavy Rain a bit of an advantage, there are things that the RPG genre could learn from PlayStation's Interactive Drama.
After all, what good is having to 'face the consequences' if the only consequences you'll have to face are at the very end of the game? Forcing characters to make tough choices early on, to live with mistakes sooner in the game creates more of an attachment. If players know they aren't really going to have to worry about things until the very end of the game, what's the point of giving choices to begin with? You might as well stick a button at the very end of the last boss fight that asks 'would you like the good or bad ending?'
Heavy Rain succeeds in this because it is a game defined by your decisions. From the most mundane aspects of your life to the more complex ones Heavy Rain will always trudge onward. Some of these choices effect the end of the game, others only change the mood of individual scenes, but either way the player is forced into an emotional connection with the characters and that's a good thing. Most of my crew in Mass Effect I found simply talking to just to see if they had anything new to say not because I was genuinely interested in what they had to say. The difference is like night and day, and that's not to say that Bioware made a bad game. They just left relationships too open, and as a result made them less intimate.
Now obviously these are two extremely different games being compared, but both of them have made similar promises. Would Mass Effect 2 been better if attacking the Collectors was put on a strict timetable? What about if character deaths meant more? Or if alliances were more susceptible to break, or harder to gain trust-wise? I feel the game would have been absolutely perfect if just for a little more of everything. Take some of that 'decision wheel' script and break it up a little bit more, feed me more information aside from when I'm forced to go to Life Support to see if maybe Thane wants to talk. Sure it was nice to be able to do things at my own pace, but a little more drama would have made the experience all the more worthwhile.