To activate the CHR RAM "Smiley Test" easter egg for this game, you will need to power on the NES/Famicom console while holding Up, Down, Left, Right, B, Select, and Start. Note, however, that it is not normally possible to hold all four D-Pad buttons without specially modified controllers; standard NES/Famicom controllers will not work.
At the high-score screen, enter one of the following phrases as your name to obtain the named effects. (Note that all of these are supposed to contain seven characters total: if there are less, then fill the rest of the name with blanks.) The effects will take place on your next playthrough of the game.
At the F16 Renegade title screen, hold one of these button combos and then press Start. Note that these only will work for 1-player mode, however.
In F16 Renegade, there are a number of cheats you can enter; however, most of the effects are variable and specific to single levels. In the table below, you will be able to see the level, the resultant effect, and the button to hold. The button you hold must be held before the level starts, and kept held until the cheat is triggered, which will be signified by a specific sound or a change in the game's palette (which may or may not be permanent).
At the title screen for this game, hold B and press Start to begin with an extra life.