Pointed Discussion

Very good.

This is an awesome landfall-utility land, bouncing Bloodghast into play or trigger other landfall effects. The "return a land" is a triggered ability that goes on the stack when Aqueduct comes into play, so this land can bounce itself every turn. Compare to Undiscovered Paradise, which sits out for a turn, vulnerable if an opponent has a Wasteland or topdecks one. With these lands that can bounce themselves, an opponent has to play their Wasteland and leave it untapped, so they can snipe your land before it bounces itself. (And if they do that, you can just choose to not play Dimir Aqueduct that turn.)

Use this with Halimar Depths.

Um, this is probably a stupid question, but if this is the first land you play or there are no other lands on the field, you an still play it, right?

Negative, Glass Joe. When the ability checks, it will notice that there is a land on the battlefield--Dimir Aqueduct. So you can play it, yes, but it will bounce itself, so that's not a very strong play.

Remember to tap the land for mana before you return it to your hand to play this.

Although the colors are not typically Landfall, it would be very useful to bounce these kinds of lands in a Landfall deck.