Dull, unemotive
Firstly, the improvements. The most noticeable change for me is that the scenery and art of the environments has been greatly improved, most worlds are very nicely designed and it is a huge step forward from mass 1 where most of the buildings planetside were identical. Generally, as you'd expect from a sequel the graphics are better and the worlds look that bit more impressive all round, especially the shiny obsidian looking blocks on the collector ship. But surely that is the minimum a sequel should do, look better than before.
Unfortunately that is the only upgrade I can find that mass 2 has over its forerunner, although different I think everything else is worse.
The plot, for example, in this first game it had you on your toes, you didn't know what was going to happen and there were some brilliant characters to back all this up. Mass 2 is comparatively dull, you start by assembling your team and then you face the collectors and win, where is the suspense in that?
There is also a lack in interesting side quests, most have you stumble upon some enemies and you kill them, seemingly for no good reason.
A major disappointment I found was 'Legion', what I thought was going to be a weird and obsessed Geth outcast leading an indoctrinated elite of Geth warriors. But no. It was one Geth and he was normal, sigh.
None of the other characters have any interesting qualities, they all have their loyalty quests but all of them include turning up and doing something you don't care about because the characters seem so dimensionless. They are well voice acted and rendered well but none of them seem very original. Like the rest of the game it just doesn't feel very convincing to me.
The combat has changed but arguably not for the better, you do get hotkeys for special abilities, which makes the combat flow better, but none of the abilities are very fun or interesting to use, save for the incendiary grenade which is awesome. The addition of heavy weapons hasn't changed much, none of the weapons in the game are particular satisfying to use.
The biggest annoyance in this game is the planet scanning. It replaces the exploration in the mako from the last game with a small rotatable globe of the planet in question which you scan with a reticule. Although few people seemed to like the mako parts of mass 1 they are preferable to spending what seems like hours going from planet to planet and dragging the sight over the surface until your pad vibrates and you release a prob. It is boring, tedious, dull, time-consuming and surely they must have designed a machine to do it, isn't that what machines are for!!!!!!
As for a summary, if you liked the first game then this a polished crap version of it with no interesting story or characters. I've played it once through completed the main story and explored half of the systems available I am severely disappointed and cannot fathom why the game needs two disks!?!?! I've done all I want to do with it and its only taken 15 hours. I understand a second playthrough may show the game to require two discs and have the story evolve differently but why would I? It is too dull to bother, I'm gonna trade it in tonight get bioshock 2 and enjoy playing a good game. How could Bioware get it so wrong? All they had to do was slightly improve the framework from mass 1 with updated graphics and it would've been a winner but it just isn't.
I'm still looking forward to mass 3, the clip at the end of the game with hundreds of reavers floating ominously towards our galaxy is a sure clue for something epic, and even though I still have my copy of mass 1 I don't want to spoil my game shelf with this poor excuse for a sequel. I have a feeling my opinion may improve if I knew what was hidden on the two discs but I can't be bothered, there is nothing interesting to draw me back for a second playthrough.
Oh, and one last thing, I doesn't matter if you've played the first game as nothing interesting happens to do with it anyway.