Can you create an endless loop? Myr Retriever specifically says return another target artifact card. Doesn't that imply that it can't return itself?

You may target another copy of Myr Retriever that is in the graveyard. When a card says "another target", it means when the effect triggers, the affected card can not be the specific card that triggered the effect. So in this case, it basically reads "When this Myr Retriever dies, you may target any other artifact in your graveyard, as long as it's not this card.

I added a 2 in front of Myr Retriever in the description to better describe the combo.

Oh, right right. I should have saw that. Makes sense.

This deck is absolutely evil and I love every bit of it!

I wanted to figure out a deck for people with little money that also wanted to play modern. It's fun.

The thing I don't like about this deck is that if you cant get any combo's in your opening hand you're a sitting duck for half of the game

That's the fault of every combo deck, man. After playing this deck as much as I have, I've rarely had a game where I've not seen a Summoning. You don't always have to have every piece of the combo in your opening hand. If this deck needed them, every time, it would only win 5% of the time. So far, I've won about 60% of the time.

Barren Moor and Polluted Mire aren't Modern legal.

Also I'd recommend running some number of Myr Moonvessel in your deck. It increases your value games with a Heartless Summoning and Grim Haruspex, plus it allows you to draw and play an Altar of the Brood. It also chumps well.

Also, Darkblast is a godsend sideboard cards. It helps against decks like Infect, while also getting Myr Retrievers in our graveyard.

Have you considered replacing a card with either demonic tutor or diabolic tutor? I feel like it's a much more direct way to get the cards you need

Diabolic Tutor was in my stack of cards initially, but Sidisi, Undead Vizier works very well with the other creatures in the deck, and adds BB for devotion.

Nice! Turn 2 win possible for under 55$

As unlikely it is to pull off, yes! But still, being able to pull off any of these combos by turn 3 is pretty cool.