Well this is a bit of a downer. Metal Slug 4 is the first entry not made by the original team at SNK, instead being helmed by MEGA and Noise Factory (who made the music of the last few Metal Slugs). And it shows. This game is a far cry from the fun as hell Metal Slug 3, which is impressive since it looks the exact same. The level and enemy design just ain't there. It's difficult without being that fun.

Remember the lil narrative bits from 1, 2/X, and 3? Well those have been toned down, this time telling of a reformed Rebel Army. The most we get is an opening cutscene and a twist during the final level. Each level also ends by Eri and Tarma from the last few games taking you to the next level. In their stead, you can play as Nadia and Trevor. While I do miss Eri and Tarma, I can't lie, Nadia and Trevor are really cool.

Now I've been a bit of downer in this review, but it's not all bad. The gameplay is still good, after all, it's still Metal Slug. Plus the final level is actually kinda good (and the music kicks ass).

You die an absurd amount in these games, let alone any run n gun, & you will die often. It is not a matter of how - you will be shot, blown up, cut up to bits, made into ground beef, turned into a mummy then dissolved, plummet to your death - it is a matter of when. Threading a needle of stray fire will only happen sometimes & what a glorious sometimes it is.

All said, you pay no mind to it. Thee deaths are inconsequential, for thee most part. What deaths ultimately represent in Metal Slug games is thee harrowing loss of yr favorite weapon type. Even parting ways with a deadly friend you knew for so little hardly hurts - you will see it again in a matter of time. It is all forgiven for just how intricate thee sprite work is, how animated each frame is, how detailed thee screen can get, how inspired these games are. Every board is a new surprise, every enemy type a new obstacle course to jump over.

Alas, this game flattens so much of those loving details. Gone are any shocks! Surprises! Twists! There isn't even an inkling of a stupidly goofy narrative or unique moments. Ah, moments. Too much is reused: sprites, ideas, challenges. MS4's idea of difficulty can be boiled & simmered to more enemies, a static stand off of incoming gunfire heading straight for you.

In all of its chaos of flashing bullets & warm flames, speeding missiles & gooey particles, I am bored.

Metal Slug is back, for the better or worse.

Metal Slug 4 is the game that revived the franchise after the massively long hiatus of 2 years since Metal Slug 3, this time being published by a fairly unknown Korean company called Mega which primarily just published Japanese games to the Korean market, though they were involved in the development of this game. Since Nazca was disbanded after the release of Metal Slug 3, the development team this time was Noise Factory, they seemed to have mostly worked on Fighting games rather than 2D Platformers and unfortunately, it showed with Metal Slug 4 being the result of this drastic change of developers for the franchise.

The game itself is still like Metal Slug 3, it plays the same with very few additions other than the double machine gun just being a variation of the heavy machine gun, and a few slugs that aren't really fun to play with.
The stages aren't really fun to play on, the enemy balance is really poorly dealt with and it's easy to get swarmed by enemies with no weapons on to deal with, the bosses are not particularly hard but not really fun either, with the final stage being most the worst one of the franchise so far.

Other than Nadia and Trevor being pretty cool new characters this game is the weakest of the bunch in general, the soundtrack is forgettable, the background art is pretty weak and shows a lot of reuse art from the older games, and the new enemies are all forgettable, the stage are generally pretty poorly designed/boring.
As a new Metal Slug game it's serviceable, as a sequel to the amazing Metal Slug 3 it's terrible.

Gameplay: Great
Story: Great (Funny)
Controls: Good
Graphics: Good (for its time)
Length: Great

Note: Played on RG35XX Retro handheld console. lol

Metal slug 4 is the fifth game instalment in the Metal slug series, and no, you don’t have to play any of the previous ones. At its core, the series is a 2D run-and-gun shooter, that has a more humorous approach to the military shooter genre. Metal slug 4 is more of the same. It neither has any innovation nor changes anything to the formula. While that would be fine for anyone who really enjoyed the previous titles, personally I was starting to get a bit bored, thus the lower rating.

Story
There is no story in the game. I don’t count anything that is outside the actual game. However, all the characters, enemies and allies, have a lot of personality simply due to their animations.

Mechanics and gameplay
If you have ever played any 2D game before, you will easily get the hang of the controls. It should be noted that auto fire is turned off by default. I was able to enable it in the settings.
You always start with the standard pistol and a few grenades. Thought the level, there are special weapons that are much more effective, although they have limited ammo. The most powerful weapons are the various vehicles. They are not only able to dispatch foes much faster, but they can also take damage.
Yeah, in Metal Slug if you get hit you die and one of your 3 lives gets used up. Since this was originally an arcade game, where higher difficulty meant more money, Metal Slug pulls no punches. There is however salvation, when your 3 lives are up you get the option to completely trivialize the game and just respawn at no cost.
I am a bit disappointed in the enemy and level variety. The last game had aliens, ancient ruins and while this focused more on robots, there wasn’t anything that grabbed my attention.

Graphics and artstyle
The artstyle is as always incredible. I believe all the sprites are hand drawn, which explains why they are so vibrant and full of life. Metal slug is the kind of series that manages to put more character in a low-level grunt, than most AAA games have in their protagonist.

Atmosphere
It’s an arcade game, so there is hardly any immersion.

Soundtrack and sound effects
SFX are great. You will always know when something dies.
The soundtrack is phenomenal. If there is one thing that you should take away from this review is that you should listen to the Metal slug 4 ost, in fact listen to all of them. Favourite part is “Secret place [stage 6]”.

Final Thoughts
Yes, I am a Marco main. How could you tell?