Alright, going into more detail about my prerelease. As I mentioned before, I went 5-1 with a B/R deck. I had a hard time deciding what color to pair with red: white had two copies of Revoke Privileges and had some flying creatures, black had removal and decent low-end creatures, and green had great creatures but no removal at all. Black was the right choice, as certain cards ended up saving my life. The one match I lost was due to mana screw, though admittedly in the first game, a lot of my issues were due to throwing away a starting hand that was color-screwed but had great cards, and then keeping a mulligan hand with just one land.
Black cards:
1x Rush of Vitality - Instant - 1B - This came in later, and I was amazed by how consistently helpful this was. Save a creature, take out a blocker, gain some life.
1x Fretwork Colony - Creature - 1B - Every time I got this out, it was a beast. I sometimes forgot the upkeep trigger, though.
1x Thriving Rats - Creature - 1B - Much more helpful than I would have thought. One time, when I had an Aethertorch Renegade bring 4 energy then die, and I started pumping the rats every attack, I realized what MaRo meant about creating variety of play with energy.
1x Essence Extraction - Instant - 1BB - Saved my life a few times.
1x Foundry Screecher - Creature - 2B - More helpful than I expected.
1x Tidy Conclusion - Instant - 3BB - Only cast this once, but I did gain 3 life that time.
1x Ambitious Aetherborn - Creature - 4B - Only got this out once, and I put the counter on it to force a trade with a big blocker.
Red cards:
1x Chandra's Pyrohelix - Instant - 1R - Mainly used it to deal 2 to a creature, but I did take out two nontoken creatures once with it, and burned someone's last 2 life.
1x Reckless Fireweaver - Creature - 1R - Only got this to ping once or twice per game it came out.
1x Aethertorch Renegade - Creature - 2R - I never got to use the player-hitting ability, due to having so few sources of energy, but the pinging was useful. This is the first time I played in a Limited environment with a pinger that hits creatures, and now I know why Wizards doesn't do them often anymore. Not only do I take out X/1s, but I can change the combat math with blockers and how much damage to worry about from a spell. Plus, the energy it brought could be used in a lot of ways.
1x Pia Nalaar - Creature - 2R - I never used the "can't block" ability, but I used the artifact power boosting much more than I thought I would. I only ever used it on the thopter she brings, though.
1x Salivating Gremlins - Creature - 2R - Usually it just didn't attack, or it attacked once after becoming a 4/3 trampler and died in combat (trading with something).
1x Fateful Showdown - Instant - 2RR - I often found myself unwilling to cast this, either because I didn't want to get rid of a card in my hand or because I didn't have enough cards to actually do any good, but it was always helpful when I did cast it. In one game, I kept passing the turn without playing any cards until I had enough to burn all my opponent's life, and then won. Another time, I used it to take out a creature, then drew a Chandra from the pillage effect. One match, I tried to take out a creature with this, and got a boost spell in response, and I thus conceded. Only after did I realize that I potentially could have drawn another burn spell from the cards I drew. Lesson is, let it play out.
1x Furious Reprisal - Sorcery - 3R - I was often able to find two targets for this, but sometimes, all I could do was hit a creature and my opponent.
1x Skyship Stalker - Creature - 2RR - A 3/3 flying firebreather really is useful. I often got it out with haste, but never with its haste ability, oddly.
1x Spontaneous Artist - Creature - 3R - I almost never used its haste ability on itself, but rather on other creatures, especially vehicles.
1x Chandra, Torch of Defiance - Planeswalker - 2RR - As expected, she was great. Often, I just used her to deal 4 damage to a creature, and she was thus immediately killed, but at least that had the effect of preventing some combat damage to me. I used her top ability twice, dealing damage both times. I used her mana ability once. I never used her ultimate.
1x Wayward Giant - Creature - 4R - Big creature, menace helped sometimes.
Artifacts:
1x Smuggler's Copter - Vehicle - This was a huge help, not just acting as a flying creature, but filtering my cards. First time I used it, I messed up and discarded before I drew a card.
1x Renegade Freighter - Vehicle - Also good, though if I had both vehicles, I favored the copter, unless I was close to winning and damage was more important.
1x Foundry Inspector - Creature - Mainly just crewed vehicles. The cost reduction ability didn't come up much.
1x Weldfast Monitor - Creature - This was a substitute for the red creature that makes creatures unable to block with energy. I had assumed that creature's ability was activated, but no, it was an attack trigger, and the perceived usefulness shot way down. I had concluded I needed more 3 mana creatures anyway, so I went for this. It was alright, I suppose.
1x Multiform Wonder - Creature - This was great, even if it only got to attack once, was blocked, and thus became a 5/1 with lifelink.
Lands:
6x Swamp
11 Mountain
Originally it was 7x Swamp and 10x Mountain, but I found myself drawing more Swamps than I wanted.