Yu-Gi-Oh! Legacy of the Duelist

Ok. So pretty straightforward achievement. Complete the 25 duels within the Classic Campaign. Reverse Duels are not required for this achievement. They are the following:

1) Yugi vs. Joey (Tutorial)
2) Yugi vs. Seto
3) Yugi vs. Weevil
4) Joey vs. Mai
5) Yuki vs. Mako
6) Joey vs. Rex
7) Yugi vs. Bakura
8) Yuki vs. Panik
9) Kaiba vs. Yugi
10) Tea vs. Mai
11) Yugi vs. Mai
12) Joey vs. Bandit Keith
13) Yugi vs. Joey
14) Yugi vs. Pegasus
15) Yugi vs. Bandit Keith
16) Yugi vs. Seeker
17) Yugi vs. Arkana
18) Joey vs. Weevil
19) Yugi vs. Strings
20) Yugi vs. Bakura
21) Joey vs. Odion
22) Seto vs. Ishizu
23) Yugi vs. Seto
24) Yugi vs. Marik
25) Yugi vs. Yugi (Yami)

Overall, the first dozen or so duels I won with the Story Deck provided. In general, the deck has the strength to win each time. The first time I really had a problem was with duel #16 versus Seeker. Here are some thoughts:

-Seeker's aim is solely to build Exodia. His monsters are usually high DEF and no attack. His one "dangerous" monster is the Red Eyes Black Dragon (2 Tributes to summon).
-The deck Yugi has uses some strong monsters, but to get them on the field could come down to luck if you don't get the right draw.
-The Chain Destruction card could technically prevent him from ever summoning Exodia (by destroying every copy in his hand and deck of a single part), but I never saw him summon any single piece of it to make the strategy work.
-Eventually, I just got the right draws to win this fight (sad to say)

In general, building an "illegal" deck to win these battles is the best strategy. When I say illegal, there are a few strategies that aren't actually allowed by using many copies of "Limited" cards. One such covered in other guides is the Exodia deck. The formula gained by defeating Seeker has 3 whole sets of Exodia. Slight changes to this formula can make an overpowered deck to win in almost no time at all.

If you don't have all the Exodia sets, a deck with much more powerful 4 star, 5 star, and 6 star (i.e. 1900 attack 4 star, 2500 attack 6 star) monsters supplemented with appropriate Traps and Spells was more than sufficient for this campaign. The strategies used by opponents are generally the most basic and the cards have the least effects especially in comparison to the other campaigns.

NOTE: Even using the non-Exodia deck, I was still using an "illegal" deck by having multiple copies of spells/traps that are limited cards. In particular, Harpy's Feather Duster was an invaluable tool at times.