Metal Slug has always been a side scrolling run and gun action game known for its charm, graphics, animation and quirky charm. Metal Slug Defense is a true departure from the genre, turning it into a side-scrolling tower defense tug of war that puts you against an army where you send out units in order to destroy the enemy base (which is really just a spawner). Its geared for a mobile free-to-play market, but its more engaging than most while still making great use of a touch screen, but mouse controls are a bit cumbersome.
It can take a while to learn the game, but its still simple to play. You have a deck of units that cost AP to send out and your AP will build up over time. Clicking Rumi when you have enough AP to do so will raise your AP cap and make your AP raise quicker. As you play your metal slug meter will build up and once its maxed out, you can send out a tank like a giant missile to take out enemies until it blows up.
Each unit is balanced to a certain degree and priced with AP accordingly. When your units are out, they will run forward and fight on their own. Some have guns, knives and others are melee or defensive. They’re unable to find cover, they just go forward until they’re within attack range and then they attack. Their only defense without building a wall of sandbags with a unit is to get hit where characters get knocked back out of range again. Sending out a unit has a cool down time before you can spawn another of the same unit.
These units have their own meter that will build up and then when fully charged, you can click on them to unleash a special ability. Even these abilities are balanced. Faster moving units have short ranged special attacks. Very slow units have long ranged attacks or they just move faster. The problem is clicking feels imprecise like clicking next to a unit will still click it. So if I’m trying to click one unit next to another, it will usually click the one next to the one I’m trying for. Sometimes its a short range ability that is just wasted. Taller units still require you to click their feet rather than their height.
The costly units are always the best. Giant crab tanks can trump anything easy levels throw at you and you can get two for the price of three good soldiers. The problem is they move very slow and can only melee by nudging into something. There are defensive units that drop sandbags and run away. These sandbags are a defensive wall for anyone behind them.
As the sortie campaign goes on you’ll fight against enemy walls, crypts that spawn mummies, subway cars that you need to fight against as they slowly melee kill your army. There’s all sorts of quirks here and there. Each area crescendos with a boss fight of some sort. One of the more memorable battles is against the giant crab that destroys a bridge with no way to melee attack it. You need to shoot it as it removes platform after platform. Its still pretty easy, but a unique twist that shows effort went into the game.
At the end of each battle, you’re given a letter grade from D to S for special. Each section of the globe has four or five levels, once you get through the levels, a new area is unlocked. There is a versus mode where you can play online against other players in one-on-one and two-on-two battles, but I’ve never been able to find a match. It keeps searching. I’ve even opted to play against any player rather than one close to my level and there’s still nothing.
To keep you playing, there are P.O.W.s to rescue one or three in each level. I feel like rescuing all of them in an area unlocked a new unit, but they at least unlock an achievement. These P.O.W.s are one of many random drops during a match that can happen. You can get cash, credits and AP boosts. If you want a P.O.W. bad enough you can spend a few medals to buy a radar item that will unlock one P.O.W. for being victorious.
Every battle you participate in costs credits that will slowly build up over time. This is part of the whole mobile mechanic to keep you coming back for more. You play for an hour, have your fun, then move on with real life and come back in a few hours or tomorrow. You’re even rewarded for coming back each day, when you should be rewarded for coming back in general.
When you replay a level you’ve already completed, you’ll see an auto button. This button lets you sit back and watch as the game plays for you. On lower levels with upgraded units its easy to win, but in later levels marked hard or very hard, that’s when you get to see how dumb the computer is when playing for you. It sends out your lesser fodder troops rather than saving up. It uses Rumi constantly raising the AP cap until its at a ludicrous level. Somehow this auto system reveals more P.O.W.s, but perhaps I am wrong.
Whether you win or lose a battle, you get cash to spend customizing your units or base and by customize, the game really means upgrading. Each unit can be upgraded with more health, but that’s it. Its your base that has the real options. Raise the maximum health of the base, decrease unit cool down time, increase your starting AP cap, increase the AP generation speed, increase the metal slug meter speed and so on. All of these can be maxed out and so can your units, so there is a sort of end game here.
Outside of the sortie campaign, there is an alternate map with levels that reset or change every X amount of minutes. I suppose its a good reason to keep coming back once you’ve maxed out everything. The entire world worth of areas are unlocked in this alternate map. Other than that there are missions to accomplish that give you a battle deck of specific units and task you with winning in under a certain amount of time. These definitely mix up the game with more armies, but I often forget about them.
The down side is these matches take less than a minute on lower levels or if you’re bad at the game. I feel its an easy game but that ease is relative based on your upgrades. That’s the problem with a grind mechanic, its too easy or too difficult.
With that said, there are multiple armies for you to face, but playing as them is a different story. While I would hope to say that completing one campaign would unlock a new army to play as, these extra armies are paid content. You get your fun for free, but you either like it so much that you’ll pay for new content or just walk away. I’ll be the person to walk away, even if I find the game fun. There’s even a King of Fighters army, which feels like the only one different than the armies already in the game. Its also twice the price of the others.
There are also medals that you earn here and there that seem to be in limited quantity. In a way it seems like this is the game’s micro transaction currency, but there’s no way that I can find to buy them with real money. So kudos to them for offering paid content rather than micro transactions. You use these medals to purchase cash which seems like an oxymoron. Other than cash you can purchase items like gas cans that maximize your AP speed, a chest that rewards your battle earnings by 1.5, a mobile satellite that attacks enemies from orbit and so on. None of these frill items feels necessary when you can just upgrade everything. Perhaps I need to be deeper into the game to need them.
The game looks excellent and sounds great. It feels like it would be at home twenty-five years ago. All the animations, characters are sprites are here. Nothing has been added. The backgrounds are fantastic, even if I barely notice them when playing. There are new big character graphics to stand by the side of menus and reveal who you will unlock for rescuing the P.O.W.s.
The menus and interface are both a bit cumbersome with a mouse. There are hot keys and buttons, but your only reminder of what they are is in the control settings section. Even a few hours in I find myself using the mouse exclusively when I should know what the hot keys are to expedite things.
Some menus require you to leave the section you’re in to go back to the main menu when there’s plenty of room for an extra menu icon for customization. You need to swipe through your deck because you can only see five or so units out of ten. You need to swipe the battlefield so you can see. Only instead of swipe, its click and drag with a mouse and it feels pretty alien. There is gamepad support, but it will only let you control the cursor rather than make use of the buttons to quick select menu items.So there you have it, an engrossing game, that forces you to come back and has paid content. It would be better as a side scrolling run and gun, but hey its fun to try different things and I think this worked out the best it could.