Contrary to popular belief, Mass Effect 2 is not better than its predecessor, in fact, it is the other way around. In the following, I will post my reasoning as to why. Beware though, this article will contain spoilers to both games, although I will try to keep them to as few as I can and as small as possible.

In the grand scheme of things, the first game feels more epic in scope from the basic things that happened to the main quest.

You felt more focussed on the outcome, rather than exploring the galaxy looking for a squad (most of who you would never use beyond their loyalty quest) and then trying to improve their loyalty (although some of the loyalty quests were well done).

The enemies of the first (Saren and Sovereign) felt to be more tangible antagonists than the collectors do in the second, you actually feel an animosity towards Saren and Sovereign and want to beat them, not just to save humanity, but just because. The collectors don't have the same menace, especially with everything you find out about them through the game.

The galaxy in the first felt more real too, you landed on a hub world and you felt as if the world was alive, in Mass Effect 2, these worlds seems smaller and more compact, especially the Citadel. Traversing the galaxy was better in the first too, whilst flying the ship around the mini-map has an enjoyable novelty effect at first, it soon wears thin as it just a novelty, I miss the days of just selecting the planet I want to go to, also, I don't understand why the ship has to undock every time you get on it (at Omega and the Citadel). Gone are the lift loading screens to be replaced by loading screens. At least with the lifts you heard talk between your squad mates and heard radio bulletins updating people based on missions you'd completed or even offering new missions.

The fact that other people would request meetings and give you side quests added to the immersion factor in the first, or you could just meet somebody, strike up a conversation and they'd ask you for something.

Whilst many people complained about the Mako sections, landing on and exploring planets was infinitely more satisfying than scanning planets from orbit.

As a final note on the state of the galaxy, the technology felt more high tech in the original, your armour could handle healing both shields and health at the same time and it had the ability for a quick health boost if you had enough medigel, whilst in the second it can't, which appears to be an attempt to shoehorn in the sit behind a box whilst you heal mechanic that is now popular. The guns seem to have been downgraded, the easily used plugin mods have disappeared and been replaced with a maximum of 3 ammo types that are squad and power based and only as a soldier on a subsequent play through will you have access to all three yourself.

The combat feels more tactical in the first, different ammo types had different uses, you had grenades that would detonate when you told them to or would detonate after a certain amount of time. Then there's your powers. You could use multiple powers as quickly as you wanted whilst in the second game if you use one power, you then have to wait for a cool-down period to use any other power, no matter how unrelated it is (for example, if you set your gun to incendiary ammo, you then have to wait a few seconds before you can use the biotic warp power).

As the difficulty level increases, the enemies just become stronger, rather than in the first where they'd gain immunities (forcing you to vary your tactics) and make more use of their respective powers.

The second game feels to have devolved in to just another corridor shooter separated by great dialogue. The majority of the RPG elements have been nearly completely stripped away, no longer do you get XP for exploration and killing enemies, rather you get it purely for completing missions.

Your decisions seem to have less weight in the overall scheme too, no longer do you have any options such as saving or destroying a colony, wiping out a species or saving the council, the decisions you do make seem to have much less weight.

It's not all bad though, the decryption and hacking mini-games have been improved, and the texture pop-in of the first is gone, but overall, I'd say the first game was the superior. The characterisation is just as good as in the first, but that's something you'd expect from BioWare.

The above is why I believe this to be the worst game BioWare have released since they started developing for consoles (I've yet to properly play the Baldur's Gate series or Neverwinter Nights so can't comment on them). That said, I still think it's an amazing game, it just doesn't live up to the high standards set by BioWare.