t ▁University ▁Category : Com mer cial ▁buildings ▁on ▁the ▁National ▁Register ▁of ▁Historic ▁Places ▁in ▁Chicago ▁Category : H istor ic ▁American ▁Build ings ▁Survey ▁in ▁Illinois ▁Category : H istor ic ▁district ▁contrib uting ▁properties ▁in ▁Illinois ▁Category : 1 8 9 0 ▁establish ments ▁in ▁Illinois ▁Category : Projects ▁by ▁Hol ab ird ▁& ▁Root <0x0A> </s> ▁J ets ' n ' G uns ▁is ▁a ▁ 2 D , ▁side - scroll ing ▁shoot ▁' em ▁up ▁computer ▁game ▁released ▁in ▁late ▁ 2 0 0 4 ▁for ▁Microsoft ▁Windows ▁by ▁Czech ▁studio ▁R ake In Gr ass ▁software . ▁In ▁April ▁ 2 0 0 6 , ▁a ▁version ▁for ▁Mac ▁OS ▁X ▁was ▁released . ▁In ▁December ▁ 2 0 0 6 ▁an ▁expansion , ▁J ets ' n ' G uns ▁Gold , ▁was ▁released . ▁A ▁version ▁for ▁Linux ▁has ▁been ▁developed ▁by ▁Linux ▁Game ▁Publishing . ▁ ▁Game play ▁Between ▁levels , ▁players ▁are ▁given ▁the ▁option ▁to ▁buy ▁up gr ades ▁for ▁their ▁ship . ▁Some ▁of ▁the ▁most ▁vital ▁up gr ades ▁are ▁for ▁man eu ver ability , ▁speed , ▁health / arm or ▁and ▁cool ing . ▁They ▁can ▁also ▁give ▁their ▁ship ▁a ▁new ▁paint ▁job ▁for ▁free . ▁Another ▁item ▁is ▁the ▁At ar ix , ▁which ▁gives ▁players ▁a ▁chance ▁to ▁un lock ▁cr ates ▁found ▁when ▁they ▁destroy ▁transport ▁ships ▁during ▁a ▁mission . ▁There ▁are ▁several ▁up gr ades ▁that ▁boost ▁the ▁ship ' s