I beat challenge #2 with a kithkin/soldier weenie deck. It was pretty straightforward; the only hard matches were Momir and
Reaper King/
Chaos Orb, neither of which even the best deck can prepare for. I swear if I ever see another third turn AI
Terravore on Momir I'll shoot myself. The real kicker came when I was praying for a
Nekrataal on my turn #4 to kill a
Terravore, got some stuipd griffin instead, and then the AI got
Nekrataal on his turn 4 and killed the griffin!
Momir mostly comes down to luck, but fortunately since it's about the third matchup, you don't lose much if it goes poorly.
Reaper King, however, is the last one. I beat Reaper by the skin of my teeth, playing defensively the whole time, saving the Orb's activation for the turn I was going to die. I pulled
Martial Coup with
X=5 (was sure glad I had 7 mana :p), blew away about five 6/6+ dudes, half of which had flying, (down to my last creature at this point) and dropped five soldiers with the AI at 6 life.
Most of the other ones aren't very hard.
Prodigal Sorcerer is mostly harmless.
Royal Assassin wasn't bad, but it can be handled; Akroma was weak, even though it grants some nice abilities, 1/1 trampling first strike goblins aren't really that scary; Oni of Whatever was a pushover since it doesn't know how to use it properly; the Green one that makes your first spell cost 1 more was annoying, but doable. That green vanguard was probably the toughest one where you actually had your own deck, and then the Assassin one.
The first matchup is kind of weird, though; the 'random' deck isn't very random. The first time I played it, the AI had (I kid you not) about twenty
Platinum Angel in its deck. Other times it was
Tetravus, or sometimes a crappy card, but there was always something it had a LOT of, and everything else seemed to be 4-ofs. I think they're still random ones, since the decks were different every time, and obviously not constructed, but the distributions seemed to be always the same (land + many 4-ofs + 1 20+-of, and a larger than normal artifact supply) and certain cards came up every single time, like
Spellbook.
edit: oh yeah the one I missed is the serra angel lifegain one. That one's easy too, because it doesn't seem to have any active threats besides
Millstone.
Recommended Strategy: Any good deck should do. Just keep slugging away until you get lucky enough to beat Momir and
Reaper King on the same run. You won't lose very often except to those two.
Reaper King in particular is quite challenging; a 6/6 on turn 3 is normal, followed by worse. Momir is at least balanced between the players, except you (hopefully!) have more skill.
Tried challenge 3 last night, but screwed up on the final matchup. (clicked wrong land and couldn't answer to a first turn
Elite Vanguard; if you've done that one, you know why this was bad news) I'll save my decklist for another thread about challenge 3. Hint:
Avatar of Hope is my secret weapon for that one :p
edit: oh yeah, for challenge 2, I used this:
;kithkin and soldier
;
;#oldgames
;
;08/08/2009
;1
;4th Edition
;
.1933 4
Figure of Destiny.1288 4
Goldmeadow Harrier.1466 4
Goldmeadow Stalwart.1414 4
Knight of Meadowgrain.1458 4
Wizened Cenn.1555 4
Preeminent Captain.1941 4
Ranger of Eos.1556 2
Captain of the Watch.1558 4
Elite Vanguard.1327 4
Field Marshal.1721 2
Kjeldoran Outpost.694 1
Karakas.188 14
Plains.1950 4
Windbrisk Heights.528 1
Strip MineThere's basically zero skill in using this deck, just dump creatures (which is all there are, no other spells) and attack with them, repeat as needed.