In the level of tournament chess, is the Traxler Counterattack just a dubious opening or a blunder? In club or online chess it works just fine, but it is one of those opening rarely seen in professional high level chess.
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1. e4 e5
2. Nf3 Nc6
3. Bc4 Nf6
4. Ng5 Bc5
I would call it dubious for most rating levels.
A computer doesn't like it too much, and you are going to lose a pawn. However, the line requires very accurate play by white to maintain that advantage. You can also get a bit of a psychological advantage here by completely ignoring your opponent's attack and focusing on your own - and if your opponent is playing the line that leads to the Traxler in the first place, they are likely a fan of attacking chess, and used to playing against defensive chess, not counter-attacking chess.
Still, you do gambit a pawn, so it is rather dubious.
At, say, the super-GM level, white is going to be able to play very accurately, and has excellent chances of at least not losing.
Gambits can be fun, and if you are not at the super-GM level (I think it's safe to assume that you aren't in the top 0.01% or whatever of chess), it can be reasonable to play.
In Karpov-Beliavsky, Moscow, 1983, Black held a draw without ever being in serious trouble. Karpov played 5.Bxf7. I have never seen detailed analysis of the game.
If it suits your style, try it. But there is a HUGE volume of analysis on it. If you play it more than once you may face a booked-up opponent.
