Enter these cheats under secrets after pausing:

Einsteinium - Big head mode
EMode - Brightness/bright colors
YourNameInLights - Credits sequence
Gilgendash - Dash not hurt when running into objects
SmartBomb - Destroy all nearby enemies and items
BoaPlace - Easier game
McTravis - Fast Running and Ramming Incredi-power
SassMode - Faster game
Kronos - Findtrails and Superpunch
AthletesFoot - Fire Trail
TonyLoaf - Health appears more often
PinkSlip - Health remains constant (not invincibility)
Dandruff - Henchmen always launch death shrapnel
Flexible - Infinite Elastigirl powers
Hi - Introduction sequence
SpringBreak - Level select
UUDDLRLRBAS - Refill 25% health
InvertTurret - Reverse movement with Nomansian Island turret
GazerBeam - Shoot beams temporarily
BWTheMovie - Slow motion player
DeEvolve - Small head mode
DiscoRules - Some objects flash different colors
DanielTheFlash - Superspeed Incredi-power while running
Showtime - Temporary infinite Incredi-points
DashLikes - Temporary infinite Incredi-power while playing as dash
bHUD - Toggle HUD
RotAIDalg - Unknown
Labombe - Unknown
TheDudeAbides - Unknown