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I don't quite understand what you're talking about - the levels are all short. None last more than 2 minutes if you know how to get around them. In fact, I think the majority last less than a minute.
It's a very hard game. The level design isn't "trial and error" - you can ALWAYS see where you need to jump, you are always informed about what hazards are there, and you are always given time at the start to get your bearings and plan a route (except in the boss battles, which do, unfortunately, contain trial and error in some cases).
It's only "bad" level design if you don't know what to do, or the traps or obstacles are hidden or you can't judge the jumps. In SMB, you can always judge the distances you have to jump, you can ALWAYS see where you need to go, the obstacles and traps are in plain sight and there are no tricks - you just avoid the sawblades, don't get hit by the lazer, don't fall off the screen, avoid the enemies, avoid the missiles, all of that is very possible. Trial and error is when you have no choice but to take random chances to see the correct path - but in SMB, the correct path is plain as day, so what part involves trial and error? Trial and Error does NOT MEAN "you die a lot". If that was the case, hell, almost any moderately difficult game could be accused of having "trial and error".
Here's what REAL trial and error is: Say for example you have two doors - one kills you, the other doesn't and you have no idea of knowing which one does which. THAT is trial and error - you have to undertake a random TRIAL and obtain information from the ERROR. Simple, no? In SMB, there is no random element. There is no hidden information. There are no hidden traps. You do not need to glean information about how to beat the level from your mistakes - if you just look at the level design, you already know how to beat the levels. So if you can't do it, that's not "trial and error", that's just difficulty.
And the controls WORK. They work really well. I've seen speed runs of SMB - I can't do them myself, but that's purely MY fault. If you and I have trouble, that's only because the game demands you to be really good. The game gives you infinite lives, an almost instant respawn and a character that can jump vast distances.
Sure, you might not like a game like Super Meat Boy. Loads of people don't like games like SMB, and that's absolutely fine. It can be frustrating. It is very hard. It can be draining and hurt your fingers, and the reward for your efforts isn't exactly worth it. I like SMB a lot, but I'd take a game like Uncharted 2 or Mass Effect 2 over it any day. Sorry, I need me my story-time and epic adventures.
But the level design is certainly not "bullshit" from a design perspective. The levels are fair, from the viewpoint that it gives you everything you need to beat them and plays no real tricks on you.
To say that the SMB level design is "bullshit" just because it has a lot of obstacles, is like saying that Chess is a bad game because it has too many pieces. Or like saying that Super Mario Brothers is bad because of those flying turtle guys that drop the hammers. It's part of the game. It's perfectly fine if you don't like it, but realize that the game was aiming for a different audience than you. It's not badly designed - it's DIFFERENTLY designed.