Deathstate

General Survival

• You always spawn at the bottom of the level, the exit is always at the top.
• Levels are random in size. There is a timer. Any opportunities you find on the way to the exit are nice, but your first priority is locating that exit.
• That said, cowards prosper in this game. You do not need to rush forward into a hellstorm of bullets as long as you continue to advance through the level. Don't be afraid to take it slow and limit the number of enemies on-screen.
• Some items and abilities are better than others. Prioritize lasers, front-loaded damage, and healing.

Mild Spoilers

• Desecration
  makes the game harder by switching up enemy attack patterns, and later increasing damage taken
  . Each of the first three worlds
  gives you a chance to desecrate somewhere on the first layer
  . You must desecrate at every opportunity
  to get the true ending
  .
• The final boss has an attack that can deal much more damage than you would come to expect after playing through the rest of the game. It's the
  black hole/portal that opens up underneath your character. You're far better off running into the current bullet pattern than risking being instakilled.
• There is a hidden "dark realm". There's no real incentive to go there, nothing new to see. To unlock it,
  stand as close as possible to a Gibberer (red mound of mouths and eyes found in the Maze of Ix that screws with your interface) and wait. You will need to hold your fire while doing this to avoid killing it, which can be done with l-shift or RT.
  Unlocking it will open portals spread across the game to make it easier to go back, if you feel the whim.