A faithfully executed retro platformer with a few nitpicks.

The levels and bosses are a bit easy in the beginning which is fine but the difficulty only seems to go up in the last few levels of the game.
There is a distracting overusage of signs in the game which are not needed because of effective visual clues and strong level design 
(for example the usage of the flickering skull signs for deadly objects. It is already clear by the design of the objects that they are deadly, so it ends up being just an annoying distraction).

More importantly the game has fun gameplay, compelling characters and enemies, feels complete and is nice to look at visually.
My favourite part is the level with the (boss)enemy that mirrors Fierce's movement. I think those kind of creative puzzle elements are one of the strengths that can be expanded upon moving forward.