Can you switch between Playthrough 1 and 2?

[Floobersman]

Just beat the story and unlocked Playthrough 2 but dont want to start it cause I haven't done all side mission in playthrough 1. So can you switch between them????

[Szyslak]

Every time you choose that character to start the game, it will ask you which playthrough you want to play. You can access either one, and it won't affect the other. They are completely independent. So feel free to go back and do your side missions, but PT1 doesn't scale, so you'll be a bit overleveled.

[Floobersman]

What do you mean dosnt scale?

[Szyslak]

The enemies in PT1 will still be at their original level. So if you're at level 37 or so, and you go back to do a side mission in the Lost Cave, the worms and skags will still be at level 14-15. There won't be much challenge.

Personally, I would only go back to PT1 to get any backpack slots you might have missed, then move on to PT2.

[RedRavyn]

What Szyslak said. I avoid any unnecessary side missions in PT1. "Necessary" are those which yield artifacts or backpack upgrades. If you do all the side missions you'll actually be over-leveled for PT2. Once I start PT2 I never look back at PT1. In both play-throughs do only the side missions you need to do in order to get those artifacts or backpack upgrades, or the occasional one to keep you at-level. Actually, I prefer to play slightly under-leveled for most missions and usually level up during them. This way I keep my character "scaled" for the game.

After PT2 start Knoxx at PT2. Don't even bother with Knoxx at PT1. Complete Knoxx and then do Zombie Island, which will scale to the player -- sort of. It scales up in increments of 5, beginning at level 10, which can give you a nasty surprise if you play there for awhile and then go elsewhere to play, then come back after getting a level to find that all your "normal" missions are now four levels above you. So: MGPT1 -> MGPT2 -> KnoxxPT2 -> ZIPT2. I can't say anything about Robolution because I haven't played that, and you don't get levels for defeating anything in Moxxie, unless you complete challenges in the process.