Mass Effect 2's final DLC is a disappointing and shallow add on that ends Mass Effect 2 on a low note.
The experience starts out with you receiving a message from Admiral Hackett asking for you to rescue an operative named Amanda Kenson who has discovered a Reaper artifact and is being held in a Batarian prison on terrorism charges. It turns out that the doctor plans on launching an asteroid into a mass effect relay on the edge of dark space to delay the inevitable Reaper invasion. Doctor Kenson is the only new character and isn't an interesting one, and the story's lack of focus makes the overall plot uninteresting to the point where it only gets decent in the final cutscene/conversation.
In addition to the lack of dialogue there are no choices to make. There was a segment that had the potential to be an excellent decision but Shepard decides to make it for you. It's unusual in addition to being disappointing because the Mass Effect series almost always let you call the shots. The story kind of picks up near the end where you have a "face to face" conversation with a character of what appears will be really important in the upcoming Mass Effect 3, and the events of Arrival will undoubtedly have large consequences.
As a way to avoid having to hire all the voice actors of your squad again and as a way to change up the combat, Bioware is having you go solo this time around. It doesn't greatly affect the game but you'll often be attacked by multiple types of enemies from a variety of angles and distances without any backup whatsoever leading to occasionally exciting skirmishes and are sometimes a bit more challenging than the main game, even though the overall DLC is way too easy. In the second half of the game you'll also be racing against the clock adding a sense of urgency when you see you only have an hour and thirty minutes to make it to the end. The problem is, it only took me an hour and thirty minutes to complete the whole add on including the intro and debriefing from Admiral Hackett, and I finished it almost half an hour before time ran out on the normal difficulty. The solo combat is still fun and a nice change of pace though.
The game tries to switch it up more by having an optional stealth sequence and giving you the opportunity to control a mech. Both are over way too quickly though and the stealth sequence is way too easy. Enemies seem completely unaware of your presence allowing you to run right behind them making you invisible as long as you're not in front of them. While breaking into the prison there's also some very simple "puzzles." The mech sequence is alright, lasting only about a minute, but it walked way too slow and was pretty forgettable. There's also a wave defense sequence in the middle of the game which is fun while it lasts, but like the rest of Arrival, is forgettable and nothing special.
Thankfully, some of Mass Effect 2's greatness returns like its lovely art design. The prison feels appropriately run down and moody and the area in which the second half of the game takes place manages to feel different from the rest of the game's indoor environments, and an area set in outer space offers a scenic view of a mass relay and the area around it. The soundtrack, however, fails to be impressive unlike the main game, which is sad because the OST helped make some moments in Mass Effect 2 even more awesome for me. Biotic and tech powers are also still fun in addition to the regular shooting and action, but it never sticks out as anything impressive.
Overall, Arrival fails to deliver and while there's some fun combat and changes to the formula, it fails to remember what made Mass Effect 2 a good game. And the DLC may end in a bang, but it ends the overall game in a whimper.