A free game that is a loving tribute to the platformers and "open world" of the ZX Spectrum/Commodore 64/NEC computer days, where the world was divided between different screens that formed the whole of a world much like VVVVVV was, rather than the scrolling with the character that came with Pitfall and Super Mario Bros. Make no mistake while this is a tribute and love letter to many a classic game in level lay out, early 80s tube computer box outline, and art style for it's game world, it is very much a game for modern design and ease of getting into.
A game where you have plenty of opportunities to learn exactly what to do due to natural and clear explanation of what to do in what is shown and required (touch an enemy and die, longer pit requires to hold the jump longer, etc), and true to it's roots it never gets too confusing in what to do or where to go unless you yourself have lost your way. It rewards mastering the jumps and wall jumps (a power up), it gives the chance for pixel perfect jumping when desired in it's normal mode, nothing is impossible to reach once you know how and can (power ups, 2 of them), and there is never a situation where one can get stuck.
As it is old school it can prove challenging to those who require a clear cut map, as none is provided and instead has one memorising the world and it's lay out until you have a good idea where to go next. As death is never a issue in it's normal mode, with Super Meat Boy like instant-respawn and an infinite number, however one is never punished for exploring and through time you learn the routes to take until they become second nature. Take as many tries as needed, never respawn too far from doing it again or leaving to try something else, it's open to you with the normal mode. As it is screen to screen, a static image as only you and enemies and some objects move in it, you learn what each one looks like with a way to remember them by a quote at the bottom to make each one stand out beyond just it's unique lay out.
Never more than a game about collecting all the money bags in the world and platforming save for one end game puzzle, which you are told how to solve by clues written on the wall, your only worry is your own skill at platforming. You jump, you wall jump eventually, you slide down, you move. The enemies are things that move from left to right or shoot small bullets in a set pattern, nothing to worry about because they never do anything different and thus you can take your time until you master them. Then, quickly speed past them and that may just be the best tactic to get through a specific screen.
As a platformer fan, as someone who loves to explore a game world, and one who enjoys creative designs with limitations on what is actually shown at any given time, I find this to just to be a spectacular and amazing game that does so many things right and is a pure example of a platformer. A game where my first play through was filled with numerous deaths, gave me the greatest sense of satisfaction in earning an achievement (Steam) when I beat the game by never dying, proving that I had mastered the game and knew exactly what to do.
Yet it doesn't even end there. For it offers a Master Quest style challenge, named Extra Spicy Mode, which completely changes up the lay out of every screen, the order in which you travel the world, the challenge offered, and you collect power ups in reverse making it that much more of a different experience. A wonderful thing to go through after I had just "mastered the game and knew exactly what to do". One section required me to do a pixel perfect landing on what normally is death for example, another learning not to jump to keep yourself alive as normal on a vertical positioned platform, and it made me work through it and improve my skill that much more without ever being unfair.
There are issues that can prevent many people from finishing it because it is challenging, those who quit games easily/rage quit may find little to love here as it's all on the player, at times easy for some to lose track of where they are or going due to no map, it won't be for all fans of platformers who want the Super Mario Bros influenced style of always moving right and holding down speed and jumping only, and there is no action/attacking some crave. Yet it is still one of the best examples of this type of platforming, a loving homage to a style very rarely seen today, and of course it's free so there is no loss in trying.
Also you can play as a cat.