Bluegrass is a perk unlocked from the beginning of Tower of Guns.
"Triple Jump from the start!"
Bluegrass gives you two additional jumps from the very beginning. This perk is very versatile, as jumping is a very important mechanic in this game. The triple jump makes finding early game secrets much easier, as well as allow one a greater degree of dodging enemy bullets. As such, it is consistently considered one of the best perks in the game, even though it is available to the player from the very beginning of his or her Tower of Guns career, to the point that the achievement for unlocking all the perks is actually called "Bluegrass is still the best". Loadouts with guns like Egon's Pride or the 609mm Hand Cannon will benefit greatly in terms of mobility from Bluegrass, allowing them to get extra mileage out of each and every jump.