Mario's Slightly Unusual Boss Rush is a game absolutely overflowing with creativity. When this game says the Boss Rush is unusual: it truly means it. Characters from media such as Ice Age and even Hilda (the animated Netflix Series based off the Children's Book series) are represented with boss fights and stages in this game. The plot is little more then an excuse plot to kick off a wacky adventure: with the Princess inviting Mario and Kamek interrupting him and sending him flying back to about 9 unique stages with 9 unique bosses in each of these.

Despite the game labeling a boss rush: it's really more of a traditional Mario game; albeit a short one. As the bosses are not fought in consistent order like you'd expect for a boss rush. You instead have to go through a small stage, each with a checkpoint and 3 collectibles inside, in order to reach the boss. And overall these are generally fully fledged Mario stages, with power-ups and small secrets in a few even. I, personally, would have likely named the game something else, as the Bosses ultimately don't come across as a particular focus in gameplay itself.

Regardless of the overwhelming creativity at hand: the fangame suffers from numerous issues that snowball into something that severely harms the overall experience. While I don't regret the fact that I played it... The amount of frustration I experienced with a small fangame is far more excessive then it had any right to be.

One of the greatest issues is Mario's control. Three Specific Points in particular: his Top Speed, his Acceleration, and his Jump Fall Speed. Controlling Mario can often be a sluggish affair: as despite the game near perfectly replicating the general aesthetics and sprite art of something like Super Mario Bros 3, with a personal twist, the game controls little like its inspiration. Jumps are exceedingly heavy, your speed is highly limited, and the fact Mario can be so sluggish can make landing precise hits on enemies or bosses an absolute nightmare. Oftentimes I would find myself overshooting what should have been simple jumps... Not at all assisted by the oftentimes confusing hitboxes of some of these foes and enemies.

Level 8: Cog, in particular, is a standout example of the game's flawed design. The sluggishness of Mario and the poor hitbox communication to the Player (The enemies of the levels, the Cogs, do not have collision on their heads) results in immense confusion. Combine this with poor telegraphing and enemy design (One particular enemy possesses a projectile attack that can be shot in 1 frame, with less then a second of cool-down between potential shots, creating an element of randomness so frustrating that you WILL find yourself yelling at the screen) and Power-up Starvation, especially post checkpoint: as there isn't a single Mushroom or Bunny Carrot for you to use to give yourself even the most minor leeway. The only thing you have is a 1-Up Mushroom left in the open: giving off the idea that this was a patchwork band-aid by the developer to cover for the immense difficulty of the level.

What are promoted as the main attraction; the bosses, are underwhelming as well. Despite the immense creativity of the foes themselves: attacks are highly limited and their hit count is ultimately left to 3. Level 4's Boss in particular is an extremely underwhelming foe. For a level based on the Ice Age films, you'd expect a far more iconic character rather then a large bird who hovers over you, hits the ground, and repeats for 2 more times.

These are just a few examples of some of the major and minor design flaws the game has as a whole, and especially for what is called a 2.0 Release: you can really see the holes, so to speak.