on Discord, @yaxu mentioned that he misses the master compressor from the original Dirt. this code is quite simple, so i decided to try implementing it for SuperDirt, with good results 
maybe others will enjoy it as well!
(actually this doesnt even depend on anything in SuperDirt, it will work with SuperCollider in general)
// emulation of master compressor from original Dirt
// requires Fb1 from miSCellaeous for single-sample feedback
// https://github.com/dkmayer/miSCellaneous_lib
(
Ndef(\dirtComp, { |amount=1, speed=50|
var in, max, env;
in = In.ar(0, ~dirt.numChannels);
max = Select.ar(ArrayMax.ar(in.abs)[1], in);
env = Fb1({ |in, out|
var env, prod;
env = out[1];
env = env + (speed / SampleRate.ir);
prod = (in[0] * env).abs;
Select.kr(prod > 1, [env, env/prod]);
}, max, leakDC: false);
ReplaceOut.ar(0, in * amount.linlin(0, 1, 1, env * 0.2));
}).play(
group: RootNode(Server.default),
addAction: \addToTail
);
)
// can also tune the parameters
Ndef(\dirtComp).set(\amount, 1);
Ndef(\dirtComp).set(\speed, 200);
edit: moved the multiplication by 0.2 into its right place