If your "Penguin Soldier" is not destroyed when its Flip Effect activates, you can use it to return the card itself to your hand along with one other monster, and then re-Set it on your next turn; this works ever better if you have another "Penguin Soldier" on your side of the field.
This is a useful card to bring back with "Salvage".
This card combos well with "Magical Hats". If your opponent's attack hits "Penguin Soldier", you can bounce the two Spell/Trap Cards you placed on the field to your hand, essentially letting you search two Spell/Trap Cards from your Deck.
This card becomes extremely useful and powerful in a Deck revolving around "Wetlands", which gives it 1950 ATK.
Using 1 "Volcanic Queen" and 1 set "Penguin Soldier", you can constantly return both monsters to your hand, to remove your opponents strongest and most dangerous monsters from the field. This can also be done with "Lava Golem" by itself or with "Volcanic Queen".
This card teams perfectly with "Ordeal of a Traveler" and "Card Destruction". Even if your opponent guesses well, their monster will be returned to his hand to be discarded by the latter.
If your opponent controls one of your monsters (such as through "Creature Swap" or "Creature Seizure"), you can use this card to return that monster to the owner's (i.e. your) hand.
This card works well in Decks that have only Level 4 or lower monsters, such as a "Kinetic Soldier" Deck. Use "Gravity Bind" to stop enemy monsters attacking, Set "Penguin Soldier", flip it up every turn, return 1 of your opponent's monsters and "Penguin Soldier", and repeat the process.
This card is wonderful for reusing your Flip Effects. If you can keep "Penguin Soldier" and another Flip Effect Monster from being destroyed, you can use the same effect multiple times. You can flip one monster over, use its effect, then flip "Penguin Soldier", return them both to the hand, and set them again. This works even better if you have "Ultimate Offering" active.
Combo this card with "Vengeful Bog Spirit"; when your opponent Summons a monster, it cannot attack your face-down "Penguin Soldier", and then on your next turn, you can return this card and the Summoned monster, creating a small lockdown.
This card is good in Anti-Meta Decks, Stun Decks, or Decks that get rid of Spells/Traps.