Goku achieved SS2 and SS3 while he was training in Other World for those seven years. In his SS2 form, he was stronger than Gohan was when he fought Cell.
episode 286
Gohan is stronger if goku is in his normal form but if they are both in super saiyan 2 form or if Goku is in super saiyan form then goku is stronger.
no goku cannot become ssj4 in buus fury because he only becomes ssj1 2 and ssj3 in the game
u have 2 be really mad at sum thing 2 become a super sayin for example goku was mad at freza for killing krillin and vegeta was mad at goku for being stronger than him and gohan was mad at cell for i dont know what
you dont get him to be his form forever u need to get the orb in goku to go super saiyan
yes he is
No.
Well Super Man may have only one weakness but Goku will lose if he doesn't turn into Super Saiyan 1, 2, 3, or 4 Super Man will win for sure but if Goku does Goku will be so powerful that he will definitely win. No problem.
his forehead is more visible in the SSJ2 form
Super Saiyan 2 goku cause he was able to defeat Broly as a Super Saiyan 1
Yes each super saiyan stage is stronger than the previous for example super saiyan 2 goku is stronger than super saiyan goku although the second stage is slower than the first stage power wise it's an improvement super siayan 3 is stronger than 2 and faster as well super saiyan 4 goku is the fastest super saiyan form (of goku only not counting fusion with vegeta) and is the last duper saiyan stage goku reaches.
Well it isn't exactly called the Time Chamber it is called the Room of Spirit and Time. and anyway Goku trained his son Gohan to become a Super Sayian and after this he fought Gohan as a sparring partner and then Goku surpassed the boundaries of Super Sayian 1 and 2 and went on to 3 and a muscle form which goku said "killed his speed".