Lil' Hunter is the boss of the Frozen City which you encounter on 5-3 and is the third boss of the game. Compared to the previous bosses, Lil' Hunter is extremely aggressive and will catch many new players off-guard. Once he drops down, you may find yourself being stomped on and killed by fire if you stay still, so moving around while fighting him is recommended. If possible, clear an area so you can concentrate when fighting him and the I.D.P.D. troops that spawn in.
- Roughly 7 seconds after entering 5-3, Lil' Hunter can be heard cackling before entering the level using his stomp attack.
- Much like the introduction phase, Lil' Hunter once again disappears off-screen, flying up into the air, before diving head-down at the player to deal impact damage and spreading blue clouds of flame in a circle around him. Watch for a shadow on the ground to indicate where he will land in order to avoid the flames as he lands on top of you. In Cooperative games, he will often use this attack to quickly jump between both players' positions if they're far away from each-other.
- Lil' Hunter fires huge numbers of red projectiles in two different patterns: High-speed streams of tightly packed red projectiles, or wide spreads of slow and bouncing red pellets. He only shoots the quick red projectiles when far away, and the bouncing red pellets when closer. Each projectile does 3 damage. While on the ground, Lil' Hunter will usually move out of your line of fire, popping out to shoot at you now and then.
- He will camp behind cover until attacked. Once in cover, I.D.P.D. Grunts will begin to teleport in near the player. Lil' Hunter will constantly peek out to fire at you while you're distracted by the I.D.P.D.. Lil' Hunter and the I.D.P.D. can damage each other which can be used to your advantage during the fight.
- Lil' Hunter will spawn more backup as his HP gets lower. A max of 6 I.D.P.D. portals can open during the fight. When Lil' Hunter is at 5/6 health there's a good chance at least one portal opened. When at 1/6 health most of I.D.P.D. units should have spawned.
- Once Lil' Hunter's HP reaches 0, due to battle damage, his jetpack will go haywire, triggering an explosion and sending him bouncing off walls. After a few seconds, his jetpack explodes again upon colliding with any wall, spawning 3 big explosions that deal major damage to anything nearby.
On loops Lil' Hunter appears after 7/(1+(number of loops/2)) seconds. That's 4.7 seconds on loop 1, 3.5 seconds on loop 2 and 2.5 seconds on loop 3.
His death explosion becomes larger. The amount of big explosions he creates on death equals (number of loops)x3.
On the first loop Lil' Hunter can spawn every regular I.D.P.D. unit. During the second loop battle he can spawn every unit including Elite I.D.P.D.. On loop 1 and 2 the max number of I.D.P.D. portals that open during the fight is the same as pre-loop, which is 6. The number of portals starts increasing after loop 2. Each loop will then add one more portal.
- Lil' Hunter was a member of the I.D.P.D., who was sent alone on a dangerous mission in a very harsh environment. After failing that mission, the I.D.P.D. abandoned him. Left with no resources and certain death, he barely survived, but went mad and mutated.
- After being abandoned, Lil' Hunter became addicted to radiation.
- Lil' Hunter was a sniper. He used very precise and stealthy methods to eliminate his targets. Currently, he will go on a rampage and destroy everything that is between him and what he thinks is his next target.
- As Lil' Hunter slowly loses the fight, in a delusional panic he calls the I.D.P.D., thinking back to when he'd call them for support. The I.D.P.D. see this as an informed opportunity for an ambush.
- Lil' Hunter used to be a close friend of Rogue but he doesn't remember her anymore.
- "Lil' Hunter's gun is named Lil' Gunther; a reference to a penguin called Gunter owned by the Ice King from Adventure Time." - Paul Veer.
- Prior to update #61, Lil' Hunter spawned the instant the player entered the level, and would mostly attack with his jetpack stomps. He was reworked to utilize his weapon more and his health was doubled, ultimately removing Lil' Hunter's "kill instantly or be killed instantly" aspect.
- Prior to update #78, Lil' Hunter would be very difficult to fight in open areas, spraying bursts of three lines of projectiles at the player. He was reworked to have "less direct firepower" and more "mean cowardly attacks". At the same time, I.D.P.D. units were added to distract the player.
- Prior to update #80, Lil' Hunter did 1 contact damage.
- Lil' Hunter's boss theme is "The One They Left Behind".