This is a fairly standard Twin Deck. I'm trying to avoid making Tarmotwin even though that might have better results at GP's and such because I'd prefer to not spend 600 extra dollars on four cards.
The Breakdown
Cryptic Command - My absolute favorite counterspell. This card gives you many options for almost any scenario you could run into. The most used mode is drawing a card and countering a spell but this can also stop a game winning attack or allow all of your tokens to get through. (Not like that's really a problem)
Deceiver Exarch - One of the main combo pieces in this type of deck. Throw Splinter Twin onto this bad boy and start making copies then untap this guy with the copy and watch people concede before you.
Desolate Lighthouse - Gains you a ton of card relevancy. By that I mean it lets you ditch cards you don't need so you can search for a combo piece and win. Amazing card and I would definitely recommend picking up a playset in case of a price spike like what happened to Gavony Township.
Flame Slash - Bolts number 5 and 6 in Modern most of the time. It's unfortunate that this isn't instant but the extra damage is the most important giving us that extra reach that a bolt doesn't have.
Izzet Charm - Works very similarly to Cryptic Command and Desolate Lighthouse because it gives us card quality and options.
Kiki-Jiki, Mirror Breaker - Functionaly the same as Splinter Twin but can't be removed in response to it being cast as it's a creature.
Lightning Bolt - A literal 3 for 1. What could you not like about this?
Peek - I'm testing this card out to see if I should run this over Probe. Probe has the benefits of being free but is only available at sorcery speed.
Pestermite - The alternate version of Exarch. This is a little worse in that it can be killed by a bolt or Anger of the Gods but it also requires less copies to kill somebody.
Remand - This is a combo deck that is based around tempo and finding your wincon so Remand fits right in. It sets your opponent back a turn most of the time and digs you deeper into your deck.
Serum Visions - The best six dollar common ever. Draws a card then sets up your next two draws or lets you see completely new cards.
Snapcaster Mage - A piker that also gives you a whole extra playset of any spells in your deck is extremely efficient.
Spell Snare - Stops most of the hard to deal with cards in the format. Deals with almost every counterspell, Tarmogoyf, Snapcaster, and Arcbound Ravager plus a ton more.
Spellskite - Great against any deck. It doesn't matter if they have relevant targeting spells or abilities it's an 0/4 wall that is very hard to get past. Great against mirror matches and Bogles.
Splinter Twin - This is what the deck was named after. When this is put on a creature that has an enter the battlefield ability it becomes insanely good and when that creature has a tap/untap ability it wins the game.
Tectonic Edge - Modern is full of utility lands and manlands both of which can be hard to deal with and Tect Edge deals with them.
Vendilion Clique - I'm currently debating over wheter to add another of these or not. Having a 3/1 flier is a great clock to put the game on even if you don't have a combo and it allows you to see what your opponent is doing or replaces a dead card in your hand.
Conclusion
So what do you all think? How should this deck be changed to be more competitive or is it good enough as is? Suggestions and +1's are appreciated!