- Awesome Art: With spritework by Paul Robertson, this is to be expected.
- Game-Breaker: Also expected, due to the Mix-and-Match Weapon customizations done by Lawless. You'd be forgiven to use them as intended instead, with all parts of the same gun (each sold separatedly) giving a reasonably boost to damage and weight, but it's when you venture out of the norm that you start to find some really broken combinations.
- One popular example are sniper rifles. They are powerful, their ammo type, Armor-Piercing/AP, travels through terrain, and as expected from such guns you can kill an enemy long before your screen borders can reach them. But their slow reload tanks the ability to spam your bullets. That is, until you can buy the Splinter, a pistol that can use AP Ammo as well, in which case your reload speed, and conversely your DPS, skyrockets to such a level that the damage penalty you'll take from using it as a receiver won't make an inch of difference.
- The same goes for the Tracker pistol, which accepts Rocket ammo. Long-range semi-homing bullet spam, yo!
- Goddamn Bats: The majority of flying enemies, many of which either home in on your position or fly in sine wave patterns and are tricky to hit until they're right up in your face.
- Grenadiers, who are among the most heavily armored infantry Mooks in the game, lob grenades that explode on impact, and are able to change their trajectories based on where you are. They're always played in just the right places to cause maximum annoyance.
- Snails, who are basically giant Metools (except they're immune to shots from behind), and who always seem to get their shots out faster than you can shoot them down.
- Hoppers. They're low enough to the ground that normal shots will fly over their head without ducking, and their jumping makes them just as aggravating as any flying enemy.
- Sentry Cannoneers, a combination of the basic Riot Griff-type enemy and Sentry Turrets. They're smart enough not to lift their shield until you're directly in their line of fire, and their hitbox is small enough that you have to do so just to hit them (no crouching right underneath their bullets while you plink away at them allowed. Not without shotgun rounds.)
- Capy Warriors not only have a longer reach than normal Runners thanks to their spears, but the spearhead takes up more vertical space than a Runner's blade, making it far easier for them to deflect oncoming bullets.
- Crypt Guards. All they really do is walk up and jab at you with their spears, and they'd be fairly easy to deal with under normal circumstances other than having a lot of hit points, but the game places all of them behind walls next to narrow platforms, where you can't hit them without AP rounds, but they sure as hell can hit you.
- Narm Charm: Much of the dialogue is clearly written with this in mind, coming off as a mix between an 80's action flick and a Saturday morning cartoon like G.I. Joe.
- That One Boss: Metal Woof. His attacks are usually fairly easy to dodge, but he has an obnoxious habit of transitioning from laser attacks into a charge attack without warning (his charge attacks, by the way, deal humongous damage and can kill you in about 2-3 hits.) He also has a full barrage that is impossible to avoid without a Riot Shield (though your first encounter graciously gives you a second out by letting you leave the stage entirely,) and even if you block it he'll still teleport before the volley dissipates to try and get in a cheap shot while you're guarding.
- That One Level: Powerhouse Alpha, which features tons of electrical traps (including a vertical climb where you have to very carefully position your jumps as you make your ascent so you don't go flying into the electric walls,) strategically placed Grenadiers, and a huge amount sealed doors that need to be blasted open with C4. A large chunk of the missions here also have a very strict time limit, meaning you'll be scrambling a lot to hurry to the supply rooms where C4 can be found and back again just to make a little bit more progress.
- The Temple is a perfect storm of aggravating traps and obstacles, Goddamn Bats and barricades that need to be blown open with C4, leading to a ton of backtracking and detours. It's bad enough that there's an achievement for beating every mission in the Major rank (where all the temple missions take place) without using any healing items.
- The missions in the Assembly Line/Cloning Facility where you have to chase down the boss are among the most aggravating in the entire game due to just how massive and full of trap and enemy-filled gauntlets the stage is. Some of the bosses have a penchant of just moving house all the way to the other end where it's nigh impossible to get to them before they move again, requiring you to instead waste time by waiting for them to go back to the arena you were just fighting in.
- They Wasted a Perfectly Good Character: Where to begin...
- Frigg, despite canonically being a member of the resistance, hardly gets any involvement in the plot or the cutscenes. They could have done alot more with her as a character than just make her a playable alternative to King or Empress.
- Majestic, Rajah, and Royal of the Mercenary Kings. Essentially they're just forgotten until its revealed that Dr. Neil made them supersoldiers for his plans. Given that they had sprites back when they were alive, they could have been made into unlockable characters after beating the game or unlocked through certain conditions when the update for the game came out in 2018.
YMMV / Mercenary Kings