None of the changes are drastic overhauls, but they do have an appreciable effect on the gameplay. One of the biggest tweaks is to the combat system. In the 360 version, you have to temporarily pause the action to use any weapons or biotic/tech powers beyond the one you currently have equipped. On the PC, this pause is still available, but weapons and powers have been consolidated onto one screen, along with squad commands which you can now issue inidividually. Pressing the space bar will bring up a heads-up display where you can change weapons or powers and issue commands to your squad. Odds are you'll use this pause very rarely, because your weapons are mapped to the function keys and your biotic/tech powers can be assigned to the number keys.
Without frequent pauses, Mass Effect further distances itself from the ponderous, tactical feel of combat in previous BioWare role-playing games. Instead, it feels like a bona fide third-person action title. Gunning down small groups of enemies while barely breaking a stride is still immensely satisfying, as is blasting your way out of larger pitched battles--only now you can unleash multiple tech or biotic attacks on the fly. You can dart out from cover, take down enemies' shields, and explode their weapons--all while shooting them--and be back behind cover in a matter of seconds. The real reward of this faster, more fluid action is the sense of power it imbues. Wielding your formidable abilities with ease really makes you feel like the badass warrior you were meant to be, and it makes combat more exciting and fun.
Unfortunately, all those tech and biotic power animations flying around can cause the frame rate to suffer on less than godly computers. This will really only happen during battles with numerous foes, and though it isn't much more than a brief stumble, it's distracting. Slightly more distracting are the frequent in-game load screens. Masked by long elevator rides on the 360, load times have actually decreased in length but increased in frequency for the PC version. Elevator rides are shorter, but you'll often be ambushed by a two- to four-second pause (the screen dims and a small "loading" icon appears) when you're coming up on a battle or entering a new area. Again, these pauses are brief enough that they don't bring things to a screeching halt, but they are a bit of a nuisance.
A few other tweaks have positive effects on the game. The inventory system is much easier to manage with a mouse and keyboard, and long lists of items won't reset to the top every time you sell something near the bottom. The Mako vehicle sequences are easier to manage thanks to the implementation of dedicated forward and reverse buttons in place of the 360 version's viewpoint-dependent controls. A new hacking and decrypting minigame, in place of the old button-matching one, is both more interesting and more suited to the game: You must move a small arrow through concentric circles to reach the core while avoiding stationary and rotating barriers. It's generally easy to accomplish once you get the hang of it, but the time limit and tricky perspective shifting help keep it entertaining. Keyboard hotkeys allow quick access to the map and squad upgrade screens, and the quicksave button is a great way to ensure you won't have to do too much backtracking. They aren't big changes, but the aggregate benefit is definitely noticeable.
All the things that made Mass Effect great on the 360--the story, the conversations, the galaxy, the combat, the soundtrack, and the characters--are still great on the PC. The changes that have been implemented don't radically alter the game in any way, but they have enough of a positive impact to make it easy to recommend the PC version over the 360 version. On top of that, BioWare is offering the downloadable expansion "Bring Down the Sky" free to PC players, though at the time of this review that content was not yet available. Whether you're a seasoned Spectre looking to suit up again, or a newcomer who has never set foot on the Normandy, the refined PC version is your best choice for experiencing this excellent game.