What does this do? Quite a bit actually. A few new weapons, a few new monsters, some new textures, some changed physics... and a few maps to demostrate all this on. Worth a look if you still got Marathon!
Yes... Exploding Barrels... the first of their kind EVER for Marathon! These are just classic original Frigidman things... worth a look if you still have Marathon.
More of a curiosity than anything else. Gives instructions on using a data fork editor to modify Gamma (and Beta) levels. Almost surely won't work on released versions.