Borderlands – Does the Hellfire weapon exist in Borderlands 2

I was hoping for a more authoritative answer, but after >50 hours of gameplay using mostly elemental weapons, I'm pretty darn sure there's no longer a tech pool.

Elemental guns deal consistent damage and elemental effects are randomly distributed. The visual effects are consistent (either a shot was elemental or not, you can tell by watching the bullet impacts).

This means that slow firing weapons are worse for stacking elemental status effect damage than high rate of fire weapons, which is sort of the opposite of how the old Tech Pool worked. The status effect chance % as listed appears to be the only relevant factor for "procing" a shot, though it's affected by skills, class mods and Badass bonus stats.

On the main menu, you will have a Select Character option. That lets you switch the active single player save. Once chosen, select Continue.

If you join another host's game, you can also choose which of these saves (characters) to play as in the first screen it shows you after you connect to the server, via the Select Character menu option.

Any progress in single or multiple is saved automatically per save. If you played co-op on the first save and progressed through the missions with others in co-op on their save (mission progression), any you complete with them will be saved on your character and you can't "go back" without creating a new character.

See How does mission progress work in multiplayer? for a description of how MP progress works when playing on other's hosts.