1) Show an Omniscience, cast Enter the Infinite.
2) Charge the Ascensions
3) Cast Burning Wish. Let the Pyromancer copies resolve, getting Golden Wish and Heat Shimmer. Before the original resolves, return it to your hand with Venser.
4) Cast Heat Shimmer. Let the first Pyromancer trigger resolve and target Venser with the copy, then have the token copy die to the legend rule and bounce Heat Shimmer. Let the second Pyromancer trigger resolve and target Venser with the copy, then have the token copy die to the legend rule and bounce the original Venser.
5) Repeat (3-4) to fetch the remaining sorceries, then repeat with Golden Wish for the enchantments.
6) Cast Forsaken Wastes, Opalescense, Vernal Equinox, and Hive Mind.
7) Cast Dual Nature, it triggers on itself. In response to the trigger, cast Venser. Stack the Venser trigger above the Dual Nature trigger. Venser bounces Dual Nature, then the copy dies to the legend rule and bounces Venser. Leave the original Dual Nature trigger on the stack. Repeat a bunch of times so you have a bunch of Dual Nature triggers on the stack. Let them all resolve so you have a large number token Dual Natures. Call this number N.
8) Use the same procedure as (7) to produce N3/2 Opalescence tokens.
9) Repeatedly cast Donate and bounce it and Venser with Venser to give away all your Opalescences.
10) Cast Venser, triggering the Dual Natures. Have the original Venser's trigger resolve first, bouncing one of the Pyromancer Ascensions. The first Venser copy dies to the legend rule and bounces the other Pyromancer Ascension. The second copy dies to the legend rule and bounces the original Venser. The remaining copies bounce themselves, so there are no Vensers on the battlefield.
11) Cast Hive Mind and Grip of Chaos, making N copies of each.
12) Cast Cultural Exchange. Your opponent gets a bunch of copies from Hive Mind, but you choose what creatures to swap when the original resolves. Choose so that your opponent controls all the Hive Minds and Grips of Chaos and the Forsaken Wastes (as well as most of the Opalescences).
13) Cast Heat Shimmer, targeting an Opalescence. If your opponent is smart, they will stack all the Grip of Chaos triggers above all the Hive Mind triggers.
14) Now, if the initial Grip triggers send the original Heat Shimmer at the Forsaken Wastes enough times, you lose. The probably of you getting hit at least once is less than N-1/2. Then, if any Heat Shimmer copy resolves targeting Forsaken Wastes before your opponent is dead, the copy removes the original and then Dual Nature removes the copy and your opponent will not lose. The probability of this happening is less than N-1/2. Assuming that doesn't happen, if enough of the copies get redirected to the Forsaken Wastes enough times, you win. The expected number of hits against the opponent is about N1/2 with standard deviation about N1/4. This puts your probability of winning close to 1 for large N. If that does not kill your opponent, you lose to a large attack.