Uh, in case they overcome you, wouldn't you like tectonic edge?

Ever thought of the card Sinister Possession?

Also check out Web of Inertia

This deck looks like a blast, you mind if I give it a build and run it. My friends might just hate me for it, But Dimir, who cares. :-)

Im putting together a side board for this deck because mana ramping creatures can get past this deck pretty easy. The side board is going to have, 4x Betrayal, 4x Power Sink, 4x Miscalculation, and 3x Slow Motion. It adds a whole new level of creature and big spell hate that is desperatley needed. Remember the point is to make them tap their land.

Mishra's Helix Deserves a spot in here some where.

Gulf Squid, Turnabout; Winter Orb if you need lock down of some kind

I had a similar deck back in the late 90s - When Rising Waters was a new card... Rising waters and Winter Orb made people sad, but they also allowed them to not untap the lands that damage them, which really slows down your clock.

Mind Over Matter maybe?

Narcolepsy is also a card. It might be better than Errant Minion as it deals with threats, but also synergies with seizures.

Stab Wound or Sinister Possession perhaps?

Maybe Fatestitcher to tap your opponent lands.

Add some Enchantment Alteration. If they lay down a Paralyze (which would be good for this deck as well) or the like you can switch it or you can switch your hurt land enchantments on the instant speed. I'm also thinking Hymn to Tourach to disrupt their hand economy as a sideboard. I would suggest a Spellskite to crush burn since that seems to be your one big weakness now.
Panoptic Mirror for the Mana Short. Rhystic Study fits into this deck like a jewel. Underworld Dreams also really hurts them, and each opponent equally well for multiplayer..

Cheers

Dark Depths is certainly a land to consider. It allows you to win if your opponent choose to slow down the game.

it's basically a death clock that force them to play fast and hence loose life through your stuff. And it's on a land so it can't be countered.

I know its a little outdated but have you considered splashing red for Citadel of Pain?

Omg Citadel of Pain is an absolute beast of a card.

It is but unfortunately it was printed when "mana burn" was a thing. Now my friends just tap out for no reason, which is fine with me, but it makes it kind awkward to use properly

But the point of the deck is to tap their lands.... So... Its awesome. They take damage no matter what.

Glad I could help :) maybe take a look at my profile? Let me know what you think of my ideas :) I made a deck similar to yours, I'll upload it soon :)

You could also try Mesmeric Orb+Gaea's Blessing

It's likely you already know this... but your opponent can tap lands for mana in response to mana web's ability. so if I tap a land Mana web tries to tap all of my other lands but I can just tap 'em all, fill my pool and spend it that phase. I will say though if I do that I'll take like 6 damage from your venomous auras... ya jerk. that said it looks like a fun deck to hate to play against. +1

Yes but with cards like Errant Minion in play they either take 2 damage or have to use all their mana in their upkeep. Which basically makes the rest of their turn useless unless they had a ton of instants in their upkeep to play. Slow Motion is in the side board for this reason as well but its only super useful if they have creature heavy decks.

The point of the deck is not to prevent them from doing things but rather make them pay for doing anything. And to give them limited choices as to what they can do and when each turn.

Doesn't seem to have enough land. Definitly agree with Stab Wound since it forces your opponents to lose life and could even be a win condition.

If you aren't worried at all about money, put in The Tabernacle at Pendrell Vale. It's great against aggro, the only creature you have is Fog Bank which you won't need once this baby comes out, and it just screws them over even more. Great deck!+1

Pendrell Mists is the vastly cheaper version of that that i have considered lol