Mouse P.I. For Hire Guide: Every Weapon Ranked and Where to Spend Your Schematics

Quick Answer: Don’t waste your limited Schematics on gimmick weapons! Max out the James Gun, Boomstick, and Devarnisher first for the best return on investment. Weapons like the D-Namite and Hellrazor require zero upgrades, saving you resources. Skip upgrading the Portable Freezer and Loose Cannon entirely unless you have materials to burn.

Mouse: P.I. For Hire scatters 89 Schematics across its levels and side jobs. You need 9 per weapon for a full upgrade sweep. Doing the math, that’s 72 Schematics to max out every eligible gun, leaving you with exactly 17 to spare.

The catch? Levels are strictly one-and-done. If you miss a Schematic, it’s gone forever. The shop won’t bail you out either. You have a tiny bit of breathing room, but your margin for error is razor-thin if you skip collectibles along the way.

Figuring out where to spend your Schematics is only half the battle. If you’re eyeing that X-1 Demousifier or just trying to figure out how to maximize your arcade payouts without losing your mind, you need to master the game’s secondary economy. I’ve broken down the fastest ways to farm what you need in my dedicated Mouse: P.I. For Hire Guide: The Token Grind Explained, so give that a read before you waste hours grinding the wrong minigames.

Two weapons ignore this system completely. The D-Namite and Hellrazor feature zero upgrade tiers. What you pick up is exactly what you keep. That simplifies your choices in a big way. Let’s break down the armory so you know exactly where to invest.

The Full Weapon Ranking (Worst to Best)

10. Mitts

These are your bare fists. You start with them out of sheer necessity. The game forces you into specific hand-to-hand sequences, and the Mitts exist purely for those scripted moments. Voluntarily throwing punches anywhere else means your ammo management has completely fallen apart.

• Best Use: Scripted encounters only.
• Schematics Priority: None. Literally cannot be upgraded.

9. Portable Freezer

Unlocked last, expected to be amazing, but heavily disappoints. Sustained ice beams freeze enemies for free damage windows, and the Alt-Fire launches an AoE frost icicle. Sounds fantastic on paper.

The glaring issue is it kills absolutely nothing on its own. Freezing a target means you still have to swap guns or land a kick to finish the job. That two-step dance kills your momentum in a game built on constant motion. Upgrades only boost freeze speed, ignoring the core damage problem.

• Best Use: Locking down a single tough enemy while your team regroups.
• Schematics Priority: Low. Save those 9 Schematics for something lethal.

8. Loose Cannon

Firing a cannonball is hilarious for roughly three encounters. Then the reload speed drives you completely crazy. Mouse: P.I. moves incredibly fast. The Loose Cannon is painfully sluggish. Single shots followed by agonizing reloads turn group encounters into sweaty survival scenarios.

It truly shines during a specific mini-boss fight where breaking walls is your main objective. The Alt-Fire turns the cannonball into a charged scattershot that handles clusters decently well, but it’s not enough to save the weapon.

• Best Use: Smashing walls and specific boss encounters.
• Schematics Priority: Low. Let the D-Namite handle the walls for free.

7. Kiss Kiss

Dropping right after you fall in love with the Boomstick, the Kiss Kiss has a steep hill to climb. The fire damage and burn DoT are fantastic for keeping enemies ticking down while you dodge. But a two-shell limit makes every pickup feel like a massive chore.

The Alt-Fire drops a heavy explosive round for solid AoE fire splash, representing the weapon at its absolute best. Upgrading gives you more projectiles and pushback, but the constant reloading never gets fixed.

• Best Use: Grouped enemies and applying burn effects.
• Schematics Priority: Skip it unless you’ve already maxed your favorites.

6. Jar-Head

Visually amazing and incredibly charming. It’s a tiny brain in a jar that shoots energy rings and literally talks to you.

Also deeply frustrating. Hit feedback is incredibly vague, and its stun-focused design leaves you constantly needing one more hit to finish the job. However, the Tier 1 upgrade unlocks a concentrated beam Alt-Fire that pops heads and deals massive burst damage. Just remember that the stun effect is entirely useless against bosses.

• Best Use: Crowd control for standard waves.
• Schematics Priority: Medium-Low. Worth Tier 1 for the Alt-Fire, but stop there.

5. D-Namite

You never actually equip the D-Namite. It sits perfectly in your offhand slot, ready to toss with a single button press without interrupting your primary gun. That one design choice makes it a top-tier tool.

It shatters walls, breaks shields, and wipes out grouped enemies. Better yet, it costs zero Schematics to maintain. It won’t carry you through a fight solo, but it perfectly patches the gaps in your arsenal.

• Best Use: Offhand utility, breaking shields, and clearing crowds.
• Schematics Priority: Irrelevant. Just throw it.

4. Hellrazor

Total DOOM vibes. A chainsaw crafted from bones that you acquire after a literal trip to Hell. It clears rooms effortlessly and throws bone projectiles for surprising range.

It requires zero upgrades and has no Alt-Fire. The base power is absurdly high right out of the box. The only real downside is the noise. It’s obnoxiously loud even when holstered, stepping all over the game’s excellent ambient sound design.

• Best Use: Close-range chaos and immediate hallway clearing.
• Schematics Priority: None. Cannot be upgraded. Enjoy the carnage.

3. Devarnisher

An early unlock that immediately proves its worth. It fires acid globs that melt enemies over time, continuously stacking damage while you focus on other threats. Ammo capacity is fantastic, letting you sustain this toxic playstyle all day.

Upgrading it pushes the projectile count higher. By Tier 1, you unlock an explosive sticky acid blob Alt-Fire that coats entire groups. For boss fights, this is arguably the most reliable damage dealer in the game.

• Best Use: Boss fights and melting health bars over time.
• Schematics Priority: High. Every tier compounds the damage beautifully.

2. Boomstick

An early find that carries you straight to the end credits. It’s a single-shot, close-range monster that drops standard grunts in one hit.

The upgrade path brilliantly fixes its flaws instead of just inflating damage numbers. Hitting Tier 2 doubles your clip size, completely transforming how the gun feels. Tier 3 lets bullets pierce three enemies in a line for free multikills. The Alt-Fire delivers a charged single shot for massive immediate damage.

• Best Use: Dominating close-range combat.
• Schematics Priority: High. Upgrade this early and max it out.

1. James Gun

The quintessential Tommy Gun. Unlocked mid-game, it immediately becomes your permanent problem solver. Best fire rate. Best ammo capacity.

Because the game expects you to burn through rounds, it constantly feeds you ammo for it. You rarely need to unequip it. Every upgrade tier boosts damage, clip size, and max ammo while reducing recoil. The Alt-Fire is a beautiful panic button that dumps your entire magazine in a wide spray to save your life. Pair it with the Boomstick to cover its reload time, and you are unstoppable.

• Best Use: Literally everything. Your definitive primary weapon.
• Schematics Priority: First. Max this before you even look at anything else.

Where to Actually Spend Your Schematics

With 89 Schematics hiding in the world and 9 required per weapon, here is the honest priority order for your resources:

You realistically have 17 Schematics of wiggle room. Treat the Tier 2 and Tier 3 groups as “nice to have” rather than guaranteed. Lock in your James Gun, Boomstick, and Devarnisher early, and treat everything else as pure optimization.

If you found this weapon breakdown helpful and want to optimize your loadouts for the rest of the game, Check out more of my guides here! Need more help surviving Mouseburg? Check out our The Ultimate Mouse P.I. Beginner’s Guide for a complete breakdown of weapons, missions, and farming routes.