It is a mobile port AND clone of Super Crate Box (the game is free on Steam - so look it up if you haven't already). I know this is enough for a lot of people to dismiss this entirely. And I don't blame them, titlescreen, menues and everything look very "tablet".
However, Muffin Knight also adds a few tweaks to Vlambeers masterpiece that make this "clone" more playable in my opinion. The most important feature is a hitpoint-system (permanent extra hits cost upgrade-points, you can take up to three hits). Allowing for some mistakes to be made compared to the insta-death-terror of SBC. Also, you have a greater variety in your movement (double jumps) as well as more varied level-layouts here (multiscreens, with teleporters and such) and towards the end of the game they even start mixing up the base gameplay (help Santa deliver gifts, reach the top of a giant beanstalk, fight a giant bossmonster) which I found quite entertaining.
The level-up system (allows you to upgrade the various characters and buy perks) and grinding for XP is more miss than hit and the most obvious reminder of a dark IAP tablet-past. But there are XP-bonus built in for doing well on the tougher levels, so overall balancing seems to work out. However, the game is so solid - all that leveling business feels unnecessary.
Anyway, it's quite an addictive little game. As every stage has it's own unique kind of rhythm (along with quite nicely done graphic sets) and once you get into the flow of things it really is plain fun. You know, that classic arcade-ish fun. Talking about arcades, I actually think this wouldn't feel too out of place in a 90ies arcade along-side games like Snow Bros. or Bubble Bobble.
Technically, as mentioned before, the menues and stuff are pretty meh! and have that mobile-look to them (you know, big, colorful buttons and "funny" fonts) - but the actual gameplay looks really nice. Big, cartoony characters, decently animated and good looking backdrops - good sense of color too (with the exception of the Windmill-stage, dat cyan!). Music is a mixed bag, there are some really amazing tunes (love the graveyard!) and also some very annoying tracks (too short, loop too soon, are annoying as hell in the process). Sound-effects are good, but the granny voice-over sounds REALLY amateurish and cheap. Also, I found that in some places hitdetection is kinda iffy and analog-controls on my 360 pad didn't work properly - had to go digital. However, once I changed the controls it was pretty good and feels really precise.
Overall a really nicely done timewaster. Not a masterpiece by any stretch of the imagination, but has a very, very solid core that will provide a couple of hours of 90ies fun. Gotta say, a pleasant surprise.