There is so much to like about Brutal Legend on face value: Tim Schafer, a heavy metal world and action/RTS hybrid gameplay. Maybe Jack Black if you swing that way. For some unfathomable reason on top of this it adds open world gameplay. Why? Tim Schafer's great strengths are good settings, good characters and genuinely funny situations and dialogue. Driving around for a few minutes to travel from mission to mission is boring, repetitive and doesn't even showcase the metal landscape. Between the mission locations, there is generic travel landscape. WoW-esque herbivores wander around low details green hills dotted with the occasional pine tree. Every so often you have to stop, look at your map, realise you've gone the wrong way and do a u-turn because there's no minimap. Monsters and enemies you get absolutely no reward for killing do their best to stop you at every opportunity. The secondary missions will make you drive a few kegs of beer to the beach party in the middle of nowhere, and then when the mission is over it makes you drive all the way back.
It's not enough to make me stop playing because everything else is good, but it feels at times as though the open world component was put it deliberately as a cheap way to extend the time it takes to play the game, which is the second greatest design crime after escort missions.