In Total Annihilation, press Enter for the message box, and then type in the cheat codes. Except for RADAR,LIGHT,SING, and other useless ones, they only work in multiplayer (if allowed) and in skirmish games. Here they are:
+AIMFROMPRIMARY -
+AIMFROMSECONDARY -
+AIMFROMTERTIARY -
+ANTIALIAS -
+ASSERT -
+ASSIGN -
+ATM - Gives you 1000 metal and energy.
+BECARRIED -
+BIGBROTHER -
+BURNALL -
+BURNONE -
+CDPLAY - Same as +CDSTART. (bit quicker)
+CDSTART - Starts CD Music.
+CDSTOP - Stops CD Music.
+CLOCK - Shows game clock.
+CONTOUR # - Displays a 3D contour, # = 1-15.
+CONTROL # - Lets you control a different skirmish AI, # = 0-3.
+DEBUGBREAK -
+DPRINT -
+DITHER - Dithering instead of line of sight.
+DOUBLESHOT - All weapons do twice the damage.
+DR -
+DROP -
+EDGE -
+FEATURE -
+FILM -
+FILMSPEED -
+FSHADOW -
+GIVE -
+HALFSHOT - All weapons do half the damage.
+IFACE -
+INCLUDE -
+ILOSE - Causes you to lose.
+IWIN - Causes you to win.
+KILL - Kills every unit. (including yours)
+LIGHT 1000 - Darker structures. No number makes them black.
+LINE%D -
+LOS - Same as +NOWISEE. (quicker)
+LOSTYPE -
+MEM -
+MEMDUMP -
+MOVE -
+MUSICMODE -
+NETSTATS -
+NOENERGY - Drops your energy to 0.
+NOMETAL - Drops your metal to 0.
+NOSHAKE - Stops explosion screen shakes.
+NOTOKTOBUILD -
+NOWISEE - Full map and disables line of sight.
+NUMLINES -
+NUMTABLES -
+OKTOBUILD -
+PROFILE -
+QUERYNANOPIECE -
+QUERYPRIMARY -
+QUERYSECONDARY -
+QUERYTERTIARY -
+RADAR - 100% radar coverage.
+RCACHE -
+RELOAD -
+SCROLLSPEED -
+SCREENCHAT -
+SEALEVEL -
+SEARCH -
+SELBOXES -
+SELECTABLE -
+SHADOW - Toggles object shadowing.
+SHOT -
+SING - This command makes units "sing" when given orders.
+SOUND3D - Toggles 3D sound
+SWEETSPOT -
+SWITCHALT - Allows you to switch between squads with # keys.
+TABLE%D -
+TABLEINFO -
+TREEDEATH -
+TSHADOW -
+VIEW # - Lets you see the metal + energy a player has, # = 0-3. +ZBUFFER -

Below is the first Campaign cheat code:
Click on Total Annihilation's Single Player icon.
When the Single Player Game page appears type
DRDEATH (it is not case sensitive). This will
cause a Cavedog Entertainment bone to appear
between the Load Game and Previous Menu icons on
the screen. Clicking on the bone will take players
to a special Play Any Game screen where they can
play any Total Annihilation mission, even if
they have not earned their way to that level yet.