Both are very mediocre as far as gameplay is concerned.
However, Half Life 2 tells a story in a far more competent fashion: it doesn't feel the need to explain everything, the story isn't completely redundant (ARRAING TEAM... which you won't use in the next game, STOP RAEPER PLOT... even though they will arrive in a few days regardless), and generally follows a "show, don't tell" motto.
Mass Effect 2, on the other hand, seems to prefer a "tell, don't show approach." Reapers are set up as some kind of unstoppable killing machines yet the game culminates with a battle against a young reaper, an army of (infinitely respawning) bad guys, and the lord of inane quotes himself (also infinitely respawning, and infinitely looping through the worst alien evil one liners ever committed to paper). You, of course, surmount this obstacle with three people, the weapons you carry with you, and some conveniently placed chest high walls. It's not the first time a game has done this, but it always annoys me.
Not to mention, Half Life 2 doesn't force me to hide behind walls and has *shock and awe* health packs. The one thing I will never understand about Half Life 2 is that the Valve clearly wished for the player to explore (some of the lambda caches, the Vortigaunt hidden in the sewer pipe) and yet they constructed their entire game out of linear levels.
However, Half Life 2 tells a story in a far more competent fashion: it doesn't feel the need to explain everything, the story isn't completely redundant (ARRAING TEAM... which you won't use in the next game, STOP RAEPER PLOT... even though they will arrive in a few days regardless), and generally follows a "show, don't tell" motto.
Mass Effect 2, on the other hand, seems to prefer a "tell, don't show approach." Reapers are set up as some kind of unstoppable killing machines yet the game culminates with a battle against a young reaper, an army of (infinitely respawning) bad guys, and the lord of inane quotes himself (also infinitely respawning, and infinitely looping through the worst alien evil one liners ever committed to paper). You, of course, surmount this obstacle with three people, the weapons you carry with you, and some conveniently placed chest high walls. It's not the first time a game has done this, but it always annoys me.
Not to mention, Half Life 2 doesn't force me to hide behind walls and has *shock and awe* health packs. The one thing I will never understand about Half Life 2 is that the Valve clearly wished for the player to explore (some of the lambda caches, the Vortigaunt hidden in the sewer pipe) and yet they constructed their entire game out of linear levels.