MURI was love at first sight.
I don't know where it suddenly came from, but it's returning me right back to my gaming roots of EGA-platforming in DOS. It looks, sounds and feels right from the start. It even lets you play in those jerky 16 frames per second that the old games used to have (optionally allowing you to smooth that out to 32 frames though). Seems like the developers sticked to the proper 16 colors palette most of the time too (to be 100% sure of that I had to look up color-tables, but... no, I am too lazy). It's really beautiful for the most part, in that 1991 kind of way of course. Kudos to whoever made the sprites and tiles, that person sure knew how it's done right. Some parts of the game are actually really atmospheric, like the dark and abandoned laboratory - very effective visual design, and quite impressive how little is actually needed to get the point across.
What's most important though, this isn't "fake" retro like most indiegames - where pixelated crap is branded "retro" to get away with it - this is truly well done and could sneak right in between Duke Nukem (the very first one, not 3D) and BioMenace.
The attention to detail doesn't stop with the nice visuals, the sound - being pretty much PC speaker beeps and bops - is spot on too. It's ridiculously cool hearing these "noises" in 2013 - not catchy chiptunes but genuine low modulation frequencies. The guys behind this made some smart choices too, like not having sound-effects on every step your character makes or an annoying bleep! when our hero jumps as it was in the original Duke Nukem.
Again, this feels like the real thing - and thus goes along nicely with the visuals. Sadly there is only one real piece of music in the game, but considering it reminds me of the first part of the Zak McKracken-theme when played via PC speaker, I am okay with that.
What really makes MURI great is the excellent gameplay. It's really simple - explore mazes, find goodies, find "cells" (which act as keycards) and use various weapon-upgrades to dispose of enemies. The mazes aren't overly complex, they feel shorter than most of the original Duke Nukem stages and aren't as complicated either, since you don't really have to get any special items like the boots or hook. Instead of making it too metroid-ish, the developers went for a more action-oriented approach - reminiscent of Turrican. Maybe even Thexder. There are tons of secret areas too - that you usually "unlock" by shooting certain walls or simply going through a wallsection that looks solid but really isn't. It's primitive, but actually quite motivating thanks to the straightforward nature of the various levels. Combat feels just as satisfying, just don't expect Metal Slug or Contra and you will be good. Particularly the higher tier weapons have a nice powerful feeling to them and are a blast (!) to use. What's nice are little modern touches like holding the attack-button making your weapon "lock" in position, so you can basically "strafe". Oh, and when I am writing "modern" I am talking about features that would have been implemented in games from say, 1992 to 1993 and weren't really common in a early nineties title like the ones this is based on. Mainly due to the fact that having pretty smooth scrolling was unbelievable tech-wizardry at the time and unless your game was REALLY rubbish the fact that it did scroll in all directions was enough reason to keep us motivated.
Enemy-variety is good as well, most scifi/retro-tropes you would expect are present here (wall-turrets, nasty bioweapons, humanoid robots). Attack-patterns have been suitably modernized to being more exciting (and challenging on higher difficulties) than actual games had back then, yet these more modern ones still feel simple enough to fit the games overall style (again, think slightly less early 90ies). Same goes for the bosses.
Going back and forth between exploration and combat helps in keeping the game fresh, relatively short levels are a boon too. You won't really get stuck and there is nearly no need for backtracking. Again, there are little modern touches that help you get along - like visible cables that lead from blown up reactors right to the now open door. MURI may look dated, but they really made sure it as playable as possible.
Finally, there is an entertaining sci-fi story happening while you keep playing, complementing the action nicely with a rather epic (in scale, at least) anime-esque tale of experiments on Mars gone wrong (where have I heard that before?) mobile-armour (Bubblegum Crisis much?), and a mother trying to save her family. Even here the game manages to mix the oldschool with some very modern flavours (especially the characterdesign of the heroine was an interesting touch).
To sum it up, MURI really surprised me in a very positive way and exceeded expectations when playing it. It's an extremely well crafted bit of oldschool fun that you shouldn't miss out on if you are familiar with the titles this game seems based on. But it doesn't need nostalgia to carry it - I do admit however it's authenticity regarding proper retro-styles did sell me on it right away. I do believe MURI stands well on it's own as an excellent example of simple but motivating gameplay done right and might be a good history lesson for the aspiring gamedesigner of tomorrow. When it comes to Retro, it is one of the finest on Steam right now.