I honestly have no idea what all of these drones are talking about in these positive reviews.
There are 30* (incorrectly said 20 before), 5-6 minute long levels. Once you've beaten it once, there's really no difficulty in beating it again, most just have one mediocre puzzle, some having no puzzle at all and just requiring you to run.
At the price point of you and your friend needing to spend $10 (previously said $20, but you get a double pack) to play this game (There is no single player), it is absolutely not worth it by ANY stretch of the imagination.
The issue with the level design is there is no varience, it is using the two items given to you at the start to solve the singular gimic. It's like getting a power up in other games, such as in Metroid Prime when you get the power shot upgrade, you already immediately know that the next solution is to use the power shot to solve it. Fortunately, in a game like that, the length allows more opportunites to use what you have in combination or solve puzzles or beat bosses, but in a game with this design, where the levels are 5 to 6 minutes long, there is no puzzle on a lot of levels, it's use the new introduced item to clear the level. The level with the potato bomb or whatever launcher and the gloves that let you pick up bigger things are clear examples, I didn't bother playing the other 10 or so that are randomly given to you until you beat so many levels or whatever the stipulation is to choose your own levels, freeing you from the chains of random selection that can force you to play through the same simplistic levels. I wouldn't recommend this game if it had 100 levels in the same style.
I'd highly suggest anyone looking to pick up a co-op game to explore other titles such as Hammerwatch or Risk of Rain at similar price points.
It's a piss poor game that promises more, but has no reason to give anymore. I don't recommend this at all.