Portals
Each Map has either two or three portals, which have their own colors and therefore special meaning. Portals can also be activated through defeating the Calamity Catalyst or beating the Maps' Boss.
Starting Portal
Upon entering the Map your starting Portal starts to get instable until it collapses. The Timer for the Portal is 3 minutes until the Portal won't be available for you to escape anymore. This can be countered by bringing Portal Flame to your expedition.
Green Portal
The Green Portal will unlock a new starting point for future runs. This means that you can randomly spawn on one of the two locations once you escaped the first time through the green Portal.
Orange Portal
The Orange Portal is the exit that is always available for you to exit. It will spawn enemies that protect the exit.