Well, okay, not entirely a piece of Gosa.
That's about it though, the rest of Mass Effect is pretty weak.
Combat system is clunky. It doesn't really have any rare items you'd expect to find in an RPG. Menu system is from the past - you can have 150 items in your inventory, but you can see maybe 3-4 items at a time - that means you'll do a lot of scrolling of menus.
Most of the planets you can visit look the same - randomly generated mountains and a few underground corridors disguised as labs and what not. They all look the same. There are perhaps 5-6 decently designed worlds in the whole game.
The vehicle sections could not be worse. Of course the developers were aiming for various gravitational environments, but your all-terrain vehicle moves like a fat man on a unicycle (zp) - wobbling all over the place. It's no fun. Vehicle's turret doesn't move properly either, you can only turn it left and right. It causes problems when flying enemies attack.
The game is bugged. You might get stuck. You might exit your vehicle and not get back in because of the rough terrain. And so in order to continue, you have to reload the game. Sometimes, in the middle of a fight controls stop responding for a few seconds... or your allies just stand still. There are also a lot of frame rate issues (think: fast slideshow speed).
The game has a lot of loading screens. Let's say you want to travel to another planet. You exit The Citadel (loading screen), travel to a different system (loading screen), change cluster (loading screen), choose a planet and land (loading screen), enter a building (loading screen).
A big part of the game is the galaxy map. It's not particularly enjoyable either because what you do is zoom in and out way too much - it doesn't give you a feeling of exploration, it's just zooming.
Quests in Mass Effect are very unrewarding. Often you don't get anything of value for completing a quest. Perhaps a pop-up window here and there, a few credits or a few tubes of medigel.
Quests are not tied to the rest of the story either. They just don't matter as much as they should in an RPG. Whether you do them or not, it hardly matters. Very. Un. Rewarding. And. Irrelevant.
[Here's hoping Mass Effect 2's gameplay will be superior in every way. ]