Well I was looking for somebody to have tried it before I went today, but nobody had so far. Two things...
First - All games do qualify including the old PS2
Second - Looks like the computer is allowing any game with at least $2 trade in value
Sadly I took 8 games and thought it was going to be 7+ games, but in fact you must hit the magic 3, 5, 7 on the nose. No bonus on the 4th, 6th, or 8th+ game. Oh Well.
Traded in just 30 min ago
Kingdom Hearts Re: Chain of Memories - $4
Kingdom Hearts - $2.50
Kingdom Hearts II - $6
GTA San Andreas - $6
Street Fighter Anniversary Collection - $3.50
Street Fighter Alpha Collection - $2.50
Mega Man X Collection - $4
Final Fantasy X - $2.50
Decided to keep Final Fantasy X and after $35 and PUR ended up with $66.35
Basically $9.50 a piece for games I can turn around and buy again for $11 a piece during any B2G1, as there are never shortages of these in my area.
Eh? You're still losing money if you do that.